MEDLINE® 2024 Database Guide
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Ovid MEDLINE® covers the international literature on biomedicine, including the allied health fields and the biological and physical sciences, humanities, and information science as they relate to medicine and health care. Information is indexed from approximately 5,600 journals published world-wide. Records start in the early 1800's and go all the way to our daily updates.

Ovid MEDLINE® is produced by the National Library of Medicine.

Non MEDLINE Status Records

The Ovid MEDLINE® database contains records with the following possible status besides MEDLINE: Publisher, In-Data-Review, In-Process and PubMed-not-MEDLINE records from NLM.

The Publisher records have recently been added to PubMed via electronic submission from a publisher, and are soon to proceed to the next stage, In-Process. This tag is also on citations received before late 2003 if they are from journals not indexed for MEDLINE, or from a journal that was accepted for MEDLINE after the citations' publication date. These citations bibliographic data have not been reviewed.

The In-Data-Review records have been submitted to NLM electronically by the publisher, and the journal title, date of publication and volume/issue (source data) are being checked.

The In-Process records are undergoing a citation level review; i.e., the author names, article title, and pagination are being checked.

The PubMed-not-MEDLINE records have undergone quality review but are not assigned MeSH headings because the cited item is not in scope for MEDLINE either by topic or by date of publication, or is from a non-MEDLINE journal. These records are constantly changing. PubMed-not-MEDLINE records will not be added to the Medline database.

Ovid receives records from NLM on a daily basis, however we are dependent upon NLM's update schedule.

Segments and Years of Coverage

The following Ovid MEDLINE segments are available to online users. Contact your local administrator to add or remove segments.

 

Single Segments
Name   Description   Years of Coverage
MED1 Ovid MEDLINE® 1946 to 1979
MED2 Ovid MEDLINE® 1980 to 1987
MED3 Ovid MEDLINE® 1988 to 1995
MED4 Ovid MEDLINE® 1996 to 2002
MED5 Ovid MEDLINE® 2003 to 2004
MED6 Ovid MEDLINE® 2005 to 2007
MED7 Ovid MEDLINE® 2008 to 2009
MED8 Ovid MEDLINE® 2010 to 2011
MED9 Ovid MEDLINE® 2012
MED10 Ovid MEDLINE® 2013
MED11 Ovid MEDLINE® 2014
MED12 Ovid MEDLINE® 2015
MED13 Ovid MEDLINE® 2016
MED14 Ovid MEDLINE® 2017
MED15 Ovid MEDLINE® 2018
MED16 Ovid MEDLINE® 2019
MED17 Ovid MEDLINE® 2020
MED18 Ovid MEDLINE® 2020
MED19 Ovid MEDLINE® 2021
MED20 Ovid MEDLINE® 2021
MED21 Ovid MEDLINE® 2022
MED22 Ovid MEDLINE® 2022
MED23 Ovid MEDLINE® 2023
MED24 Ovid MEDLINE® 2023 to 2024
MED25 Ovid MEDLINE® December 2023 Week 4 to July Week 2 2024
MEDL Ovid MEDLINE® July Week 3 2024 to Present
MEDP Ovid MEDLINE® Epub Ahead of Print Updated Daily
MEDV Ovid MEDLINE® Versions All Versions with Weekly Update
MESX Ovid MEDLINE® Updated Daily
PMED Ovid MEDLINE® Practice Database 2000
PMNM1

Ovid MEDLINE® PubMed-Not-MEDLINE

1946 to 1999
PMNM2

Ovid MEDLINE® PubMed-Not-MEDLINE

2000 to 2012
PMNM3

Ovid MEDLINE® PubMed-Not-MEDLINE

2013 to 2016
PMNM4

Ovid MEDLINE® PubMed-Not-MEDLINE

2017 to 2019
PMNM5

Ovid MEDLINE® PubMed-Not-MEDLINE

2020
PMNM6

Ovid MEDLINE® PubMed-Not-MEDLINE

2021
PMNM7

Ovid MEDLINE® PubMed-Not-MEDLINE

2022
PMNM8

Ovid MEDLINE® PubMed not MEDLINE

2023
PMNM9

Ovid MEDLINE® PubMed not MEDLINE

December 16, 2023 to August 12, 2024
PMNM

Ovid MEDLINE® PubMed-Not-MEDLINE

August 13, 2024 to Present
PREM Ovid MEDLINE® In-Process & In-Data-Review Citations Updated Daily

 

Multi-Segments
Name   Description   Years of Coverage
MEDALL Ovid MEDLINE® ALL 1946 to Daily Update
MDFC Ovid MEDLINE® 1996 to Present with Weekly Update
MDXC Ovid MEDLINE® 1996 to Present with Daily & Weekly Update
MEDB Ovid MEDLINE® 1946 to 1995
MEDF Ovid MEDLINE® 1996 to Present with Weekly Update
MEDW Ovid MEDLINE® 2020 to Weekly Update
MEDX Ovid MEDLINE® 1996 to Present with Daily Update
MESD Ovid MEDLINE® 1946 to Present with Daily Update
MESZ Ovid MEDLINE® 1946 to Present with Weekly Update
MEZZ Ovid MEDLINE® 1946 to Present with Weekly Update
OMES Ovid MEDLINE® 1946 to Present with Daily Update
OMME Ovid MEDLINE® 1946 to Present with Weekly Update
PMEZ Ovid MEDLINE® and In-Process, In-Data-Review & Other Non-Indexed Citations and Daily 1946 to Present
PMFC

Ovid MEDLINE® and In-Process, In-Data-Review & Other Non-Indexed Citations

1996 to Present
PMOZ Ovid MEDLINE® and In-Process, In-Data-Review & Other Non-Indexed Citations and Daily 1946 to Present
PMNMW

Ovid MEDLINE® PubMed-Not-MEDLINE

2020 to Present
PMNMZ

Ovid MEDLINE® PubMed-Not-MEDLINE

1946 to Present
POMM Ovid MEDLINE® and In-Process, In-Data-Review & Other Non-Indexed Citations 1946 to Present
PPEM Ovid MEDLINE® Epub Ahead of Print and In-Process, In-Data-Review & Other Non-Indexed Citations Updated Daily
PPEZ Ovid MEDLINE® and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations and Daily 1946 to Present
PPEZV Ovid MEDLINE® and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations, Daily and Versions 1946 to Present with Daily & Weekly Update
PPFC Ovid MEDLINE® and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations 1996 to Daily Update
PPFF Ovid MEDLINE® and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations 1996 to Present with Daily & Weekly Update
PPMC Ovid MEDLINE® and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations and Daily 2020 to Daily Update
PPMW Ovid MEDLINE® and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations and Daily 2020 to Daily Update
PPMZ Ovid MEDLINE® and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations 1946 to Present
PREW Ovid MEDLINE® In-Process & In-Data-Review Citations 1946 to Present
PRMF Ovid MEDLINE® and In-Process, In-Data-Review & Other Non-Indexed Citations 1996 to Present with Daily & Weekly Update
PRMZ Ovid MEDLINE® and In-Process, In-Data-Review & Other Non-Indexed Citations 1946 to Present

The limit of databases that you can select for a multifile search session is based upon database segments rather than actual databases. The Ovid multifile segment limit is set at 120 to avoid impacting your search sessions. This database includes 40 segments.

This database is updated online daily and weekly.

Fields
The following list is sorted alphabetically by field alias. Click a field name to see the description and search information.
All Fields in this Database
Abbreviated Source (AS) Entry Date (ED) Other Abstract (OA)
Abstract (AB) Equal Contributor (EC) Other ID (OI)
All Searchable Fields (AF) Exploded MeSH Heading (XM) Page (PG)
Anatomy Supplementary Concept (MY) Exploded Subheading (XS) Personal Name as Subject (PN)
Anatomy Supplementary Concept Word (MX) Floating Sub-heading (FS) Place of Publication (PL)
Article Identifier (ID) Floating Sub-heading Word (FX) PMC Identifier (PM)
Authors (AU) Gene Symbol (GS) Population Supplementary Concept (UL)
Authors Full Name (FA) Gene Symbol Word (GW) Population Supplementary Concept Word (UX)
Author Last Name (AX) General Note (NT) Primary Author (PA)
Author Name ID (AI) Grant Acronym (GR) Protocol Supplementary Concept (PS)
Beginning Date (BD) Grant Country (GC) Protocol Supplementary Concept Word (PX)
Book Accession (BK) Grant and Funding Information (GI) Publication History Status (PH)
Book Authors (BA) Grant Number (NO) Publication Status (PP)
Book Authors Full Name (BF) Grant Organization (GO) Publishing Model (PI)
Book Edition (BN) Indexing Method (IG) Publication Type (PT)
Book Editors (BE) Institution (IN) Publisher (PB)
Book Part (PR) Investigator (IR) Publisher Item Identifier (DI)
Book Title (BT) Investigator Affiliation (IA) Pubmed Central Release (PQ)
Book Volume (BV) Investigator NameID (IX) Rare Disease Supplementary Concept (RS)
Registry Number/Name of Substance (RN) ISBN (IB) Rare Disease Supplementary Concept Word (RX)
Cited Reference Date (CQ) ISO Journal Abbreviation (IO) Record Owner (RO)
Cited Reference DOI (CD) ISSN Electronic (ES) Reference Title Index (RL)
Cited Reference Issue (RP) ISSN Linking (IL) Report Number (RR)
Cited Reference Page (CG) ISSN Print (IS) Revision Date (RD)
Cited Reference PMCID (CZ) Issue/Part (IP) Season (SE)
Cited Reference Publisher Identifier (RY) Journal Name (JN) Secondary Source AN (SA)
Cited Reference Source (CS) Journal Subset (SB) Secondary Source ID (SI)
Cited Reference UI (RZ) Journal Word (JW) Secondary Source Link (SL)
Cited Reference Volume (CE) Keyword Heading (KW) Section (SN)
Cited References (RF) Keyword Heading Owner (KO) Source (SO)
Collection Title (CL) Keyword Heading Word (KF) Space Flight Mission (SM)
Comments (CM) Language (LG) Status (ST)
Conflict of Interest (CI) Media Type (MT) Subject Heading Word (HW)
Contribution Date (CB) MeSH Date (DA) Synonyms (SY)
Copyright Index (CR) MeSH Subject Headings (SH) Text Word (TW)
Corporate Author (CN) Name of Substance Word (NM) Title (TI)
Country of Publication (CP) NLM Journal Code (JC) Title Comment (TC)
Create Date (DT) NLM Journal Name (NJ) Unique Identifier (UI)
Date of Publication (DP) NLM Journal Word (NW) Update Date (UP)
Digital Object Identifier (DO) Number of References (NR) Version Date (VD)
Editors (EE) Object ID (OJ) Version ID (VI)
Editor Last Name (EX) Organism Supplementary Concept (OS) Volume (VO)
Editors Full Name (FE) Organism Supplementary Concept Word (OX) Volume Book Title (VB)
Electronic Date of Publication (EP) Original Title (OT) Year of Publication (YR)
Ending Date (ET)    
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Default Fields for Unqualified Searches (MP): Searching for a term without specifying a field in Advanced search, or specifying .mp., defaults to the following ‘multi-purpose’ (.mp.) fields for this database: ti,bt,ab,ot,nm,hw,fx,kf,ox,px,rx,ui,sy,ux,mx.
Abstract (AB) Name of Substance Word (NM) Rare Disease Supplementary Concept Word (RX)
Anatomy Supplementary Concept (MY) Organism Supplementary Concept Word (OX) Subject Heading Word (HW)
Book Title (BT) Original Title (OT) Synonyms (SY)
Floating Sub-heading Word (FX) Population Supplementary Concept Word (UX) Title (TI)
Keyword Heading Word (KF) Protocol Supplementary Concept Word (PX) Unique Identifier (UI)
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Default Fields for Display, Print, Email, and Save: The following fields are included by default for each record.

Abstract (AB) Investigator Affiliation (IA) Record Owner (RO)
Authors (AU) Keyword Heading (KW) Source (SO)
Author's Full Name (FA) MeSH Subject Headings (SH) Secondary Source Link (SL)
Registry Number/Name of Substance (RN) Original Title (OT) Status (ST)
Date of Publication (DP) Other Abstract (OA) Title (TI)
Institution (IN) Other ID (OI) Unique Identifier (UI)
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All Fields for Display, Print, Email, and Save: Use the Select Fields button in the Results Manager at the bottom of the Main Search Page to choose the fields for a record.

Abbreviated Source (AS) Editors Full Name (FE) Place of Publication (PL)
Abstract (AB) Gene Symbol (GS) PMC Identifier (PM)
Article Identifier (ID) General Note (NT) Protocol Supplementary Concept (PS)
Authors (AU) Grant Acronym (GR) Publication History Status (PH)
Authors Full Name (FA) Grant Country (GC) Publication Status (PP)
Author Name ID (AI) Grant and Funding Information (GI) Publisher Item Identifier (DI)
Beginning Date (BD) Grant Number (NO) Publishing Model (PI)
Book Accession (BK) Grant Organization (GO) Publication Type (PT)
Book Authors (BA) Indexing Method (IG) Rare Disease Supplementary Concept (RS)
Book Authors Full Name (BF) ISSN Linking (IL) Record Owner (RO)
Book Edition (BN) ISSN Electronic (ES) Report Number (RR)
Book Editors (BE) Institution (IN) Revision Date (RD)
Book Part (PR) Investigator (IR) Season (SE)
Book Title (BT) Investigator Affiliation (IA) Secondary Source AN (SA)
Book Volume (BV) Investigator NameID (IX) Secondary Source ID (SI)
Registry Number/Name of Substance (RN) ISBN (IB) Secondary Source Link (SL)
Collection Title (CL) ISO Journal Abbreviation (IO) Section (SN)
Comments (CM) ISSN Print (IS) Source (SO)
Conflict of Interest (CI) Journal Subset (SB) Space Flight Mission (SM)
Contribution Date (CB) Keyword Heading (KW) Status (ST)
Copyright Index (CR) Language (LG) Synonyms (SY)
Country of Publication (CP) Local Messages (LM) Title (TI)
Create Date (DT) Media Type (MT) Unique Identifier (UI)
Date of Publication (DP) MeSH Date (DA) Update Date (UP)
Digital Object Identifier (DO) MeSH Subject Headings (SH) Version Date (VD)
Editors (EE) NLM Journal Code (JC) Version ID (VI)
Editor Last Name (EX) NLM Journal Name (NJ) Volume Book Title (VB)
Electronic Date of Publication (EP) Object ID (OJ) Year of Publication (YR)
Ending Date (ET) Original Title (OT)  
Entrez Date (EZ) Other ID (OI)  
Entry Date (ED) Other Abstract (OA)  
Equal Contributor (EC) Personal Name as Subject (PN)  
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Elements of Source (SO) Field: Ovid searches the following fields as part of the record source.
Book Edition (BN) Issue/Part (IP) Season (SE)
Book Title (BT) Journal Name (JN) Volume (VO)
Book Volume (BV) Page (PG) Year of Publication (YR)
     
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The following list is sorted alphabetically by the two-letter label, and includes the relevant alias, at least one example for all searchable fields, and a description of the field.
Label Name / Example
AB Abstract [Word Indexed]
f108.ab.

Since 1975, NLM has included author-written abstracts from journals whose publishers gave the NLM permission for their use. These abstracts appear in the Abstract (AB) field. Over 50% of the documents in Ovid MEDLINE(R) contain abstracts. The abstract index contains all searchable words from the abstract.

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AF All Searchable Fields [Search Alias]
heart.af.
All Fields (AF) is an alias for all of the fields which occur in the source documents, including value-added fields such as MeSH Subject Headings (SH).

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AI Author NameID [Word]
5371.ai.
Author NameID (AI) field contains author's full name and its unique identifiers may be supplied by the publisher for records added or updated beginning in January 2013. The identifier may be an Open Researcher and Contributor ID (ORCID), an International Standard Name Identifier (ISNI),Ringgold, or from the Virtual International Authority File (VIAF).

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AS Abbreviated Source [Display Only]

The Abbreviated Source (AS) field includes a display of all the basic information needed to locate a citation, including the Journal Abbreviation (JA), the Volume(VO), Issue/Part (IP), Page (PG) and Date of Publication (DP).

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AU Authors [Phrase Indexed]
zzaman s.au.

The Authors (AU) field contains the authors of the article.  The format for authors is last name followed by one or more initials:  Smith JC or Smith J. Enter the last name, or if it is a common name, enter the last name and first initial. If you are unsure of the spelling of the last name (macdonald or mcdonald), enter one version and then scroll through the list of names to find the other.

Misspelled and corrected names are now included in the Author Index to ensure all possible matches. Only correct author names display, while incorrectly spelled names are indexed along with the correct spelling of the name.

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AX Author Last Name [Phrase Indexed]
fabiola.ax.
The Author Last Name (AX) index allows you to search for the authors’ last names. Author names display in Authors (AU) and Authors Full Name (FA) fields.
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BA Book Authors [Phrase Indexed]
board on health sciences policy.ba.
The Book Authors (BA) field contains the list of authors associated with the book article. The format for authors is last name followed by one or more initials: Smith JC or Smith J. Enter the last name, or if it is a common name, enter the last name and first initial.

This field is displayed in the Authors (AU) field.

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BD Beginning Date

Waiting for NLM's feedback.
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BE Book Editors [Phrase Indexed]
frostig rd.be.
The Book Editors (BE) field contains the list of editors associated with the book article. The format for authors is last name followed by one or more initials: Smith JC or Smith J. Enter the last name, or if it is a common name, enter the last name and first initial.

This field is displayed in the Editors (EE) field.

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BF Book Authors Full Name [Phrase Indexed]
coffey.bf.
The Book Authors Full Name (BF) field contains the full name of the book authors of the article when available.

This field is displayed in the Authors Full Name (FA) field.

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BK Book Accession

The Book Accession (BK) field contains Bookshelf accession numbers for citations for books and book chapters from the NCBI Books Database. This url will link directly to the specific book citation in the NCBI Books database.
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BN Book Edition [Word Indexed]
2nd.bn.
The Book Edition (BN) field contains the edition information of book citations. This information displays as part of the Source (SO) field.
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BT Book Title [Word Indexed]
aerodigestive.bt.
The Book Title (BT) field appears in book citations only, and contains the title of the book in which the chapter appears.

This information displays as part of the Source (SO) field.

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BV Book Volume [Word Indexed]
samplevol1.bv.
The Book Volume (BV) field contains the volume information of book citations. This information displays as part of the Source (SO) field.
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CB Contribution Date

The Contribution Date (CB) field contains the date when the Pubmed book article was contributed.
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CD Cited Reference DOI [Phrase Indexed]

The Cited Reference DOI (CD) field contains the DOI information of the source citation.

This field displays in the Cited References (RF) field.
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CE Cited Reference Volume [Word Indexed]
103.ce.
The Cited Reference Volume (CE) field contains the particular volume of the Cited Reference Source (CS).

It displays in the Cited References (RF) field.
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CG Cited Reference Page [Word Indexed]
011002.cg.
The Cited Reference Page (CG) field contains the page information of the source citation.

It displays in the Cited References (RF) field.
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CI Conflict of Interest [Word Indexed]
Merck.ci.
The Conflict of Interest (CI) field contains disclosure statements as provided by the publisher. This field was introduced in 2017.
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CL Collection Title [Word Indexed]
frontiers.cl.
The Collection Title (CL) field contains the title of book collection where the book citation belongs to.
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CM Comments [Word Indexed]
e296.cm.
The Comments (CM) field contains the comment or correction type and the corresponding codes as displayed in below table. Please note the Title Comment (TC) field contains the detail of the referenced article.

Comment or Correction Type Code Description
Comment in (CIN) cites the reference containing a commentary about the article (appears on citation for original article); began use with journal issues published in 1989.
Comment on (CON) cites the reference upon which the article comments; began use with journal issues published in 1989.
Erratum in (EIN) cites a published erratum to the article (appears on citation for original article); began use in 1987.
Erratum for (EFR) cites the original article for which there is a published erratum. As of 2016, partial retractions are considered errata.
Corrected and Republished in (CRI) cites the final, correct version of a corrected and republished article (appears on citation for original article). Began use in 1987 as Republished in (RPI); renamed in 2006.
Corrected and Republished from (CRF) cites the original article subsequently corrected and republished. Began use in 1987 as Republished from (RPF); renamed in 2006.
Dataset described in (DDIN) cites a description of a dataset.
Dataset use reported in (DRIN) cites articles reporting results or use of a dataset.
ExpressionOfConcernIn (ECI) cites the expression of concern (appears on citation for original article); began use in 2017.
ExpressionOfConcernFor (ECF) cites the original article for which there is an expression of concern; began use in 2017.
Republished in (RPI) cites the subsequent (and possibly abridged) version of a republished article (appears on citation for original article); began use in 2006.
Republished from (RPF) cites the first, originally published article; began use in 2006.
Retraction in (RIN) cites the retraction of the article (appears on citation for original article); began use in August 1984 but applied back through 1966.
Retraction of (ROF) cites the article(s) being retracted; began use in August 1984 but applied back through 1966.
Update in (UIN) cites an updated version of the article (appears on citation for original article); began limited use in 2001.
Update of (UOF) cites the article being updated; limited use; began limited use in 2001.
Summary for patients in (SPIN) cites a patient summary article; began use in November 2001 (these records contain Publication Type, Patient Education Handout).
Original report in (ORI) cites a scientific article associated with the patient summary.
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CN

Corporate Author [Phrase Indexed]

The Corporate Author (CN) field identifies the corporate or collective authorship of an article. Corporate names display exactly as they appear in the journal.
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CP

Country of Publication [Phrase Indexed]
new zealand.cp.

The Country of Publication (CP) field contains the full name of the country in which an article was published. The country name is entered into the index as a phrase.
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CQ

Cited Reference Date [Phrase Indexed]
1880 aug.cq.

The Cited Reference Date (CQ) field contains at least the publication year for the respective reference. This field may contain month, day and/or time of publication or release.

This field displays in the Cited References (RF) field.
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CR

Copyright Index [Word Indexed]
reserved.cr.

The Copyright Index (CR) index contains published information and it will be display at the end of Abstract (AB) or Other Abstract (OA) field if available. The Copyright Index (CR) is a word indexed.
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CS

Cited Reference Source [Word Indexed]
acs med chem lett.cs.

The Cited Reference Source (CS) field contains the journal name of the source citation.

The Cited Reference Source displays in the Cited References (RF) field.
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CZ Cited Reference PMCID [Phrase Indexed]

The Cited Reference PMCID (CZ) field contains the PMC identification number of the source citation reference.

It displays in the Cited References (RF) field.
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DA

MeSH Date [Phrase Indexed]
20190116.da.

The MeSH Date (DA) field contains the date MeSH terms were added to the citation. The MeSH date is the same as the Entrez date until MeSH are added. This field has a format display of YYYY/MM/DD HH:MM and the index format is YYYYMMDD.
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DI Publisher Item Identifier [Phrase Indexed]
s1413.di.

The Publisher Item Identifier (DI) field uniquely identifies individual published documents that are provided by the publisher for new citation submitted. The full PII appears as such e.g .S0036-36342008000600005.

Search all PII's by replacing punctuation with spaces such as "S0036 36342008000600005".di. for the displayed PII of S0036-36342008000600005.

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DO Digital Object Identifier [Phrase Indexed]
pi 2013 662065.do.
The DOI (DO) field contains the Digital Object Identifier - a unique and persistent digital identification code for any object of intellectual property. The DOI itself consists of two parts: a prefix which is assigned to each publisher by the administrative DOI agency, e.g., "10.1097", and a suffix which is assigned by the publisher and can be any code that the publisher chooses, e.g., "00045415-200111000-00002". The full DOI appears as such: "10.1097/00045415-200111000-00002". Search all DOI's by replacing punctuation with spaces such as "10 1016 j adnc 2003 08 001".do. for the displayed DOI of 10.1016/j.adnc.2003.08.001. (all DOI information provided to Ovid is loaded as it becomes available from NLM).
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DP Date of Publication [Phrase Indexed]
summer 2016.dp.
The Date of Publication (DP) field consists of the date of publication for a citation, in the format YYYY MMM DD (1950 dec 3). The Month and day are not always present. This field is also displayed as part of the Source (SO) field.
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DT Create Date [Phrase Indexed]
20190116.dt.
The Create Date (DT) field contains the date when it was added to PubMed. It was implemented with all PubMed records when the 2009 system became available on December 15, 2008. All records added to PubMed prior to implementation received a Create Date equal to Entrez Date (EZ). This field has a format display of YYYY/MM/DD HH:MM and the index format is YYYYMMDD.
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EC Equal Contributor
ahmed.ec.
The Equal Contributor (EC) field contains the journal publisher names who submit citation data to Pubmed.
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ED Entry Date [Phrase Indexed]
20130215.ed.
The Entry Date (ED) field contains the NLM internal Date Completed (DCOM) which is the date processing of the record ends; i.e., MeSH Headings have been added, quality assurance validations are completed, and the completed record subsequently is distributed to PubMed. This is contrasted with the PubMed/MEDLINE Date Created, which is the date processing begins.

Format: YYYYMMDD
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EE Editors [Phrase Indexed]
sankaranarayanan r.ee.
The Editors (EE) field contains the list of editors associated with the book article. The format for editors is last name followed by one or more initials: Smith JC or Smith J. Enter the last name, or if it is a common name, enter the last name and first initial.

The Editor (EE) field is phrase indexed.

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EP Electronic Date of Publication [Phrase Indexed]
20091023.ep.

The Electronic Date of Publication (EP) is the date the record was sent to NLM for inclusion in MEDLINE (R). This index appears in the format YYYYMMDD.

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ES ISSN Electronic [Phrase Indexed]
0003 3898.is.

The ISSN Electronic (ES) field contains the Electronic International Standard Serial Number (EISSN) for the journal in which an article was published. It appears as an 8 digit number, separated by a hyphen: 0028-4793. To retrieve all of the articles for a journal, search by the Journal Name (JN).

Both Electronic and Print ISSNs can be searched in the ISSN Print (IS) field.

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ET Ending Date
2016.et.
Waiting for NLM's feedback.
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EX Editor Last Name [Phrase Indexed]
gelband.ex.
The Editor Last Name (EX) index allows you to search for the Editor's last names. Editor names display in Editors (EE) and Editors Full Name (FE) fields.
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EZ Entrez Date [Phrase Indexed]
20190116.ez.
The Entrez Date (EZ) is the date the citation was added to PubMed. However, prior to October 9, 2008, the Entrez Date was set equal to the Publication Date (DP) on records with publication dates before September 1997. Beginning on October 9, 2008, the Entrez Date is set equal to the Publication Date (DP) when the record enters PubMed more than twelve months after the date of publication. This field has a format display of YYYY/MM/DD HH:MM and the index format is YYYYMMDD.
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FA Authors Full Name [Word Indexed]
gaaied.fa.

The Authors Full Name (FA) field contains the full name of the authors of the article when available.

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FE Editors Full Name [Word Indexed]
hellen.fe.

The Editors Full Name (FE) field contains the full name of the editors of the article when available.

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FS Floating Sub-Heading [Phrase Indexed]
legislation jurisprudence.fs.

Subheadings are qualifiers added to MeSH subject headings to refine their meaning. Terms such as "etiology" or "therapy," when combined with a MeSH heading, give a precise idea of what an article covers.

The Floating Sub-Headings (FS) field contains both the 2-letter codes, such as "po," and the full heading, such as "poisoning." These are displayed following the corresponding MeSH Subject Headings.

      Code   Floating Subheading       Code   Floating Subheading       Code   Floating Subheading
  ab  

Abnormalities

      en  

Enzymology

      pc  

Prevention & Control

  ad  

Administration & Dosage

      ep  

Epidemiology

      px  

Psychology

  ae  

Adverse Effects

      es  

Ethics

      re  

Radiation Effects

  ag  

Agonists

      eh  

Ethnology

      rt  

Radiotherapy

  aa  

Analogs & Derivatives

      et  

Etiology

      rh  

Rehabilitation

  an  

Analysis

      ge  

Genetics

      sc  

Secondary

  ah  

Anatomy & Histology

      gd  

Growth & Development

      st  

Standards

  ai  

Antagonists & Inhibitors

      hi  

History

      sn  

Statistics & Numerical Data

  bi  

Biosynthesis

      im  

Immunology

      sd  

Supply & Distribution

  bl  

Blood

      in  

Injuries

      su  

Surgery

  bs  

Blood Supply

      ir  

Innervation

      tu  

Therapeutic Use

  cf  

Cerebrospinal Fluid

      is  

Instrumentation

      th  

Therapy

  cs  

Chemical Synthesis

      ip  

Isolation & Purification

      to  

Toxicity

  ci  

Chemically Induced

      lj  

Legislation & Jurisprudence

      tm  

Transmission

  ch  

Chemistry

      me  

Metabolism

      tr  

Transplantation

  cl  

Classification

      mt  

Methods

      td  

Trends

  co  

Complications

      mi  

Microbiology

      ul  

Ultrastructure

  cn  

Congenital

      mo  

Mortality

      ur  

Urine

  cy  

Cytology

      nu  

Nursing

      ve  

Veterinary

  df  

Deficiency

      og  

Organization & Administration

      vi  

Virology

  dg  

Diagnostic Imaging

      ps  

Parasitology

  di  

Diagnosis

      py  

Pathogenicity

  dh  

Diet Therapy

      pa  

Pathology

  de  

Drug Effects

      pk  

Pharmacokinetics

  dt  

Drug Therapy

      pd  

Pharmacology

  ec  

Economics

      ph  

Physiology

  ed  

Education

  pp  

Physiopathology

  em  

Embryology

  po  

Poisoning

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FX Floating Sub-Heading Word [Word Indexed]
abnormalities.fx.

Sometimes you may wish to retrieve every Floating Sub-Heading that includes a particular word; this is done by searching the single word in the Floating Sub-heading Word (FX) field.

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GC Grant Country [Phrase Indexed]
united states.gc.
The Grant Country (GC) field contains the country of the organization that awarded the grant.

This field displays as part of the Grant and Funding Information (GI) field.

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GI Grant and Funding Information [Phrase Indexed]
hhsn263201200074i.gi.
The Grant and Funding Information (GI) field displays information about awarded grants, may contain Grant Number (NO), Grant Acronym (GR) or funding organization acronym, Grant Organization (GO) and Grant Country (GC).
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GO Grant Organization [Word Indexed]
nih.go.
The Grant Organization (GO) field contains the full name of the organization that has awarded the grant.

This field displays as part of the Grant and Funding Information (GI) field.

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GR Grant Acronym [Phrase Indexed]
od.gr.
The Grant Acronym (GR) field contains contains the 2-letter grant code or funding organization acronym that has awarded the grant.

This field displays as part of the Grant and Funding Information (GI) field.

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GS Gene Symbol [Phrase Indexed]
16s rrna.gs.

The Gene Symbol (GS) field contains Gene Symbols as they are entered into Ovid MEDLINE(R) in the original document. They often, but not always, conform to standardized human gene nomenclature.  Ignore super or sub-scripts in entry of a gene symbol:  psub 1450 would be entered p1450. Enter hyphens as in the original symbol.

The Gene Symbol field was added to Ovid MEDLINE(R) in 1991.  Beginning in 1996, data will no longer be added to this field.

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GW Gene Symbol Word [Word Indexed]
0602.gw.
The Gene Symbol Word (GW) index contains individual words from the Gene Symbol (GS) field.  The Gene Symbol field was added to Ovid MEDLINE(R) in 1991.  Beginning in 1996, data will no longer be added to this field.
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HW Subject Heading Word [Word Indexed]
EMPLOYMENT.hw.

The Subject Heading Word (HW) index allows you to retrieve every MeSH subject headings and Publication Type that include a particular word. Do this by searching a single word in the Subject Heading Word (HW) field.

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IA Investigator Affiliation [Word Indexed]
acute.ia.

The Investigator Affiliation (IA) field contains author's full name and its affiliation to the investigator of the article.

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IB ISBN [Phrase Indexed]
9781464803697.ib.
The ISBN (IB) field contains the International Standard Book Number (ISBN) and is found only on citations for book and book chapters from the NCBI Books Database.

The ISBN (IB) field appears as a 10-digit number and may contain 13-digit number if available.

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ID Article Identifier [Phrase Indexed]
zwi10767fm pii.id.
The Article Identifier (ID) field may contain an identifier that links with records in the publisher's system. The Article Identifier values may include the controlled Publisher Identifier (PII) or the Digital Object Identifier (DOI). It is most often used for LinkOut, and is not considered part of the citation source information.
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IG Indexing Method
automated.ig.

The Indexing Method (IG) field was introduced by the NLM in September 2018. It will only be present in records if a value is specified. If Indexing Method is not present in status MEDLINE records, the indexing method is fully human indexed.

Values for Indexing Method (IG) are:

Curated – MeSH indexing is provided algorithmically and a human reviewed (and possibly modified) the algorithm results
Automated – MeSH indexing is provided algorithmically
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IL

ISSN Linking [Phrase Indexed]
0003 2670.il.

The ISSN Linking (IL) index contains an identifier intended to provide a mechanism to group the various medium versions of a continuing resource. The purpose of the ISSN-L is to provide a mechanism for grouping, or collocating, the various medium versions of a resource, for instance, the print and online versions of a journal per ISO 3297 standards. "The first ISSN assigned, in the ISSN Register, to any medium version of a continuing resource shall be designated by default to function also as the ISSN-L and shall apply to all other media versions of that resource identified in the ISSN Register.

The ISSN Linking field will be used only for new records added during the 2008 production year (although NLM still does not know the timing when all will be in place to start to appear on records).

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IN Institution [Word Indexed]
lzy.in.

The Institution (IN) field contains the author's full name and its affiliation, which is usually the source for a reprint of the article. This information can be searched in most documents since 1988, but records from earlier years which were added to the database after 1988 may also contain institution information. Beginning with documents indexed in 1996, author's email address will also be included, if present in the journal.

The information is taken from the source document and is not standardized. Enter the single most descriptive word in an institution (harvard, not university). Consider both full spellings and abbreviations.

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IO ISO Journal Abbreviation [Phrase Indexed]
zygote.io.
The ISO Journal Abbreviation (IO) field contains journal abbreviations. Those created prior to 2007 did not necessarily conform to the ISO standard. ISO Journal Abbreviations created after this date are identical to the Journal Abbreviation (JA) field. In November 2009 ISO abbreviations were retrospectively assigned for every record from a journal that was currently indexed for MEDLINE at that time.
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IP Issue/Part [Word Indexed]
1808.ip.
supplement.ip.
The Issue/Part (IP) field contains the Issue and/or part for a particular volume of a journal. This field usually displays as part of the Source (SO) field.
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IR Investigator [Phrase Indexed]
barrowman n.ir.

The Investigator (IR) field contains personal names of individuals (e.g., collaborators and investigators) who are not authors of a paper but rather are listed in the paper as members of a collective/corporate group that is an author of the paper. The format for authors is last name followed by one or more initials: Smith JC or Smith J.

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IS ISSN Print [Phrase Indexed]
8756 971x.is.

The ISSN Print (IS) field contains the International Standard Serial Number (ISSN) for the journal in which an article was published. It appears as an 8 digit number, separated by a hyphen: 0028-4793. To retrieve all of the articles for a journal, search by the Journal Name (JN). Both Electronic and Print ISSNs can be searched in the IS index.

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IX Investigator NameID [Phrase Indexed]

The Investigator NameID (IX) field is defined to contain a unique identifier associated with the name. The values in the Identifier attribute Source will designate the organizational authority that established the unique identifier.

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JA Journal Abbreviation [Phrase Indexed]

The Journal Abbreviation (JA) field contains the abbreviation of the journal in which the article was published.

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JC NLM Journal Code [Phrase Indexed]
9891704.jc.
The NLM Journal Code (JC) is an alpha-numeric code established by NLM which uniquely identifies every journal indexed in the NLM databases. Only the 7 digit code is searchable, in some cases the 3 digit alpha-numeric code will display as well.
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JN Journal Name [Phrase Indexed]
aesthetic surgery journal.jn.

The Journal Name (JN) field contains the full name of the journal in which the article was published. Journal names are indexed as phrases, so enter enough letters of the journal name to locate the name in the index:  new engl (for New England Journal of Medicine). This field usually displays as part of the Source (SO) field.

If the first word of a Journal Name is "The", it has been stripped off.

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JW Journal Word [Word Indexed]
chemosphere.jw.
The Journal Word (JW) index contains individual words from every journal name in Ovid MEDLINE(R). This field displays as part of the Source (SO) field.
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KF Keyword Heading Word [Word Indexed]
seizure.kf.

The Keyword Heading Word (KF) index allows you to retrieve every Keyword Heading assigned by authors that include a particular word. Do this by searching a single word in the Keyword Heading Word (KF) field. 

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KO Keyword Heading Owner [Phrase Indexed]

The Keyword Heading Owner (KO) field contains an acronym that identifies the organization that provided the Keyword Heading (KW) data. The Keyword Heading Owner (KO) acronyms and their respective organizations are:

Acronym = Organization

KIE = Kennedy Institute of Ethics, Georgetown University
NASA = National Aeronautics and Space Administration
PIP = Population Information Program, Johns Hopkins School of Public Health
NLM = National Library of Medicine (used for the OLDMEDLINE records)
NOTNLM = (The journal publisher or other data provider. This is used when the Keyword Heading (KW) field includes author-supplied keywords. NLM began using this value in January 2013.)

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KW Keyword Heading [Phrase Indexed]
dacryocystitis differential diagnosis.kw.

The Keyword Heading (KW) field contains the Keyword Headings assigned by authors. Keyword Headings are the author keywords. To retrieve every Keyword Heading that includes a particular word, search for the word in the Keyword Heading Word (KF) field.

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LG Language [Phrase Indexed]
greek.lg.
The Language (LG) field contains the language(s) of publication of an article. The language name will appear in the index as the full form and a 3-letter code (such as fre for French) and as the full name French. The codes are usually, but not always, the first three letters of the language name.

The language index is quickly scrollable to determine all languages which appear in Ovid MEDLINE(R).

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LH Locally Held [Display Only]
The Locally Held (LH) field indicates (with a "Y" or an "N") if a journal is held locally.
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LM Local Messages [Display Only]
The Local Messages (LM) field contains messages created by the System Administrator to indicate information about journals held in your local library system.
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MT Media Type [Word Indexed]
internet.mt.
The Media Type (MT) field identifies the physical medium of the book citation(s) that are available.
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MX Anatomy Supplementary Concept Word [Word Indexed]
The Anatomy Supplementary Concept Word (MX) index allows the users to retrieve single terms from the Anatomy Supplementary Concept (MY) field.
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MY Anatomy Supplementary Concept [Word Indexed]
The Anatomy Supplementary Concept (MY) field contains the Protocol Class 6 SCR terms. The Anatomy Supplementary Concept (MY) terms are phrase indexed.

They appear for the first time in the 2023 MeSH.

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NJ NLM Journal Name [Phrase Indexed]
zygote cambridge england.nj.
The NLM Journal Name (NJ) field contains the full name of the journal in which an article was published.
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NM Name of Substance Word [Word Indexed]
zucchini.nm.

The Name of Substance (NM) index contains single words from the CAS Registry/EC Number/Name (RN) field and is used to search portions of chemical names. This field displays as part of the CAS Registry/EC Number/Name (RN) field.

The Name of Substance (NM) field was added to Ovid MEDLINE(R) in 1980.

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NO Grant Number [Phrase Indexed]
hhsn276201400262u.no.
The Grant Number (NO) field contains the original identification number of the grant that is awarded to the work as described in the content. The identification number is assigned by the grant agency.

This field displays as part of the Grant and Funding Information (GI) field.

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NR Number of References

The Number of References (NR) field contains the number of bibliographic references listed in the review article.

Effective October 1, 2010 NLM discontinued the practice of including the number of bibliographic references listed in articles cited in MEDLINE. NLM had included the number of references for the following Publication Types: Review; Consensus Development Conference; Consensus Development Conference, NIH; Interactive Tutorial; Meta-Analysis. This change in policy is prospective only; we will not remove number of references data from existing citations.

This field displays in the Abstract (AB) and Title (TI) when available.

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NT General Note [Word Indexed]

The General Note (NT) field contains general supplementary information about an item. The notes may include information on the availability of a bibliography, ordering information for dissertations or hearings, or general summaries of materials such as manuals or scripts. A series title may appear for a book or for audiovisual materials.

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NW NLM Journal Word [Word Indexed]
laboratory.nw.
medicinal.nw.

The NLM Journal Word (NW) index contains individual words from every journal name in the NLM Journal Name (NJ) field.

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OA

Other Abstract [Word Indexed]
sabemos.oa.

The Other Abstract (OA) field can include the Collaborating Partner, a brief abstract, Copyright and Language of the Other Abstract. The OA field is indexed in the Abstract (AB) field, and contains all searchable words from the Other Abstract.

Collaborating Partners include:

AAMC

American Association of Medical Colleges; not currently used

AIDS

Special HIV/AIDS publications with abstracts written by someone other than the author

KIE

Kennedy Institute of Ethics, Georgetown University; not currently used

PIP

Population Information Program, Johns Hopkins School of Public Health; not currently used

NASA

National Aeronautics and Space Administration; not currently used

Publisher

journal editorial staff, typically for citations to older articles that did not contain abstracts when originally published
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OI Other ID [Phrase Indexed]
vapa676772.oi.

The Other ID (OI) is a unique alpha-numeric code. In particular, it will contain the PubMed Central Identifier (PMCID), where the alphabetical prefix 'PMC' precedes the identifier. If the publisher has embargoed access to the full text, the date of availability in PubMed Central will be noted. When the embargo is lifted, a revised record with the date of availability removed will be released.

Other ID's are entered into the index as phrases. In particular, PMC ID's should be searched as how the alpha-numeric code appears in PubMed Central (PMC).

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OJ Object ID

Waiting for NLM's feedback.
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OS Organism Supplementary Concept [Phrase Indexed]
tomato yellow leaf curl virus.os.

The Organism Supplementary Concept (OS) field contains the Protocol Class 4 SCR terms that includes viruses and other organisms. The Organism Supplementary Concept (OS) terms are phrase indexed.

They appear for the first time in the 2018 MeSH and were made available as a means to index emerging viruses and other pathogenic organisms as they occur in the literature without delay

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OT Original Title [Word Indexed]
nachbarschaft.ot.
The Original Title (OT) includes any non-English titles in the original language. If the original title was in a non-Roman alphabet, then the OT is transliterated.
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OX Organism Supplementary Concept Word [Word Indexed]
virus.ox.

The Organism Supplementary Concept Word (OX) index allows the users to retrieve single terms from the Organism Supplementary Concept (OS) field.

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PA

Primary Author [Phrase Indexed]
zywiel mg.pa.

The Primary Author (PA) index contains the first author listed for the article. This allows users to search for articles by any primary author. Author names display in Authors (AU) and Authors Full Name (FA) fields. Searching for smith rh.pa. will return results where Smith RH was listed as the main author of the article.

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PB

Publisher [Word Indexed]
biomed.pb.

The Publisher (PB) index contains publisher information for books, monographs or any non-journal publications. This information is taken from the source document as it appears, so variant forms of a publisher are possible. This field is usually displayed as part of the Source (SO) field.

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PG Page [Phrase Indexed]
e012.pg.

The Page (PG) field consists of the inclusive pagination of a journal article. Often a journal title combined with the beginning page number is enough to locate a citation. You can search for pages with alphanumeric characters, such as "a1.pg." This field displays as part of the Source (SO) field.

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PI Publishing Model [Display Only]

The Publishing Model (PI) field provides the model of publishing of the original document described in the record. The field indicates if the article cited is available in Print or Electronic format. It also indicates if the citation was converted from a Print or Internet source. This field is display only; you cannot search this field.       

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PH Publication History Status [Word Indexed]
revised.ph.

The Publication History Status (PH) field contains information from the publisher regarding important events in the publishing process. It contains a date, and one of the following values for each date in the publication history:

[received] - date manuscript received for review
[accepted] - accepted for publication
[revised] - article revised by publisher or author
[aheadofprint] - published electronically, to be followed by the print

The Publication History Status (PH) field is word-indexed.
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PL Place of Publication [Word Indexed]
southampton.pl.
The Place of Publication (PL) field contains the name of the town or city where the book was published. This field is only available on Ovid MEDLINE® Epub Ahead of Print (MEDP) segment.
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PM PMC Identifier [Phrase Indexed]
pmc999$.pm.
The PMC Identifier (PM) is a unique alpha-numeric code. In particular, it will contain the PubMed Central Identifier (PMCID), where the alphabetical prefix 'PMC' precedes the identifier. If the publisher has embargoed access to the full text, the date of availability in PubMed Central will be noted. When the embargo is lifted, a revised record with the date of availability removed will be released.

Other ID's are entered into the index as phrases. In particular, PMC ID's should be searched as how the alpha-numeric code appears in PubMed Central (PMC).

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PN Personal Name as Subject [Phrase Indexed]
sacks ow.pn.
The Personal Name as Subject (PN) index includes the name of a well-known person if they are discussed in an article, such as an interview or obituary.

The format for Personal Name is the same as for Author -- last name and initials:  Bach JS.  Enter a last name and one initial if known.
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PP Publication Status [Word Indexed]
ppublish.pp.
The Publication Status (PP) field contains the current status of the publication, as submitted by the publisher. Possible values are:

ppublish - published in print (default value)
epublish - electronically published only, never published in print
aheadofprint - electronically published, but followed by print
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PQ Pubmed Central Release [Phrase Indexed]
"2019 08 18".pq.

The Pubmed Central Release (PQ) field contains the embargo date associated with the availability of the published article in PMC.

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PR Book Part [Word Indexed]
chapter.pr.
The Book Part (PR) field contains the chapter number where the book title appears in the citation.
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PS Protocol Supplementary Concept [Phrase Indexed]
gemcitabine oxaliplatin regimen.ps.

The Protocol Supplementary Concept (PS) field contains the Protocol Class 2 SCR terms. These terms were previously exported in CAS Registry/EC Number/Name of Substance (RN) in MEDLINE/PubMed. The PS terms are phrase indexed.

With the 2011 reload, Protocol Supplementary Concept (PS) were loaded separately only for new records added during 2011 production year.

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PX Protocol Supplementary Concept Word [Word Indexed]
anavacym.px

The Protocol Supplementary Concept Word (PX) index allows the users to retrieve single terms from the Protocol Supplementary Concept (PS) field.

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PT Publication Type [Phrase Indexed]
journal article.pt.
published erratum.pt.

In addition to indexing documents with Medical Subject Headings, the indexers at the National Library of Medicine assign terms to describe the article type. Publication Types include such classifications as reviews, clinical trials, directories and letters. These terms appear in the Publication Type (PT) field.

To view the index, enter enough letters to distinguish a publication type (jour for "journal article"); the entire index is quickly scrollable to determine all possible publication types.

With the 2005 reload, Publication Types are also loaded into the MeSH. Because some Publication Types are also MeSH terms, the syntax to enter the Tree is "Randomized controlled trial [publication type]". To post the results from the Tree without entering the Tree, the syntax is: "Randomized controlled trial [publication type]"/ or Randomized controlled trial.pt.

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RD Revision Date [Phrase Indexed]
20031107.rd.
The Revision Date (RD) field contains the issue (year, month and day) in which a document was revised in Ovid MEDLINE. The RD field appears in the format YYYYMMDD. Previously, the RD field was indexed with the Entry Date (ED) field. Now, it is a separate index.
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RF Cited References
Use RF to simultaneously search in all searchable parts of the Cited References field, including Cited Reference Date (CQ), Cited Reference Authors, Cited Reference Source (CS), Cited Reference Title, Cited Reference DOI (CD), Cited Reference Volume (CE), Cited Reference Page (CG), Cited Reference Issue (RP), Cited Reference PMCID (CZ), Cited Reference Publisher Identifier (RY) and Cited Reference UI (RZ).
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RL Reference Title Index [Word Indexed]
The Reference Title Index (RL) allows the users to search for the reference(s) title which may contain one or multiple source citations.

It displays in the Cited References (RF) field.
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RN Registry Number/Name of Substance [Phrase Indexed]
zzt404xd09 tipranavir.rn.

The RN field can contain the following:
- The unique 10-digit Unique Ingredient Identifiers (UNIIs) assigned by the Food and Drug Administration (FDA) Substance Registration System (SRS)
- The 5- to 9-digit Chemical Abstracts Service (CAS) for Registry Numbers
- The number EC derived from Enzyme Nomenclature to designate a particular enzyme

Examples:

To find UNII number 8R78F6L9VO (Sumatriptan) search for: 8R78F6L9VO Sumatriptan.rn. or: 8R78F6L9VO*.rn.
To find CAS number 54-16-0 (Hydroxyindoleacetic Acid)), search for: 54-16-0 Hydroxyindoleacetic Acid.rn.
To find EC number (EC 1-14-14-1 (Aryl Hydrocarbon Hydroxylases)), search for: ec-1-14-14-1 aryl hydrocarbon hydroxylases.rn.

A zero (0) is a valid value when an actual number cannot be located or is not yet available. E.g. search for: 0 Pulmonary Surfactants.rn

Note: NLM has not added Chemical Abstracts Service (CAS) registry numbers to MeSH since 1998, therefore only registry numbers that were previously available are displayed in the MEDLINE record.

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RO Record Owner [Phrase Indexed]
hsr.ro.

The Record Owner (RO) field contains the owner of the record.

HMD

History of Medicine Division, National Library of Medicine

HSR

Health Services Research

KIE

Kennedy Institute of Ethics, Georgetown University

NASA

National Aeronautics and Space Administration

NLM

National Library of Medicine

PIP

Johns Hopkins University Center for Communication Programs
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RP Cited Reference Issue [Word Indexed]
10030.rp.
The Cited Reference Issue (RP) field contains the issue information of the journal in which the citation appears.

It displays in the Cited References (RF) field.
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RR Report Number [Word Indexed]
sma.rr.

The Report Number (RR) field contains the primary identification number of a report. This is normally the number given to the report by the issuing organization (not the US Government Clearing House Number). Inspec treats IEEE Standards as reports.

The Report Number (RR) field is word indexed so any part of the report number can be searched separately, if desired.
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RS Rare Disease Supplementary Concept [Phrase Indexed]
17 hydroxysteroid dehydrogenase deficiency.rs.

The Rare Disease Supplementary Concept (RS) field contains the Protocol Class 3 SCR terms. The RS terms are phrase indexed.

Beginning with 2011 MEDLINE/PubMed data, Rare Disease Class 3 SCRs are also going to be exported.

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RX Rare Disease Supplementary Concept Word [Word Indexed]
leukoencephalopathy.rx

The Rare Disease Supplementary Concept Word (RX) index allows the users to retrieve single terms from the Rare Disease Supplementary Concept (RS) field.

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RY Cited Reference Publisher Identifier [Phrase Indexed]
The Cited Reference Publisher Identifier (RY) field contains the Publisher Item Identifier (DI) of the source citation.

It displays in the Cited References (RF) field.
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RZ Cited Reference UI [Phrase Indexed]
1000201.rz.
The Cited Reference UI (RZ) field contains the PMID of the source citation.

It displays in the Cited References (RF) field.
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SA Secondary Source AN [Word Indexed]
S78411.sa.

The Secondary Source AN (SA) index contains the unique identifiers of outside resources discussed in MEDLINE articles. The display will include the Secondary Source ID (SI) and the unique identifier separated by a forward slash (GENBANK/S78411). If you wish to search all works from a particular databank use the Secondary Source ID (SI) index: refseq.si.

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SB Journal Subset [Phrase Indexed]
om.sb.
oldmedline citations.sb.

The Journal Subset (SB) field identifies the subset for MEDLINE records from certain journal lists on specialized topics. The NLM discontinued the Journal Subset (SB) indexing for MEDLINE/PubMed with the 2022 reload, with the exception of "index medicus.sb." and "oldmedline citations.sb.". Ovid replaced the corresponding Journal subset limits new journal selections based on NLM Catalog searches, using matching MeSH terms and title words to create new lists of titles for the below journal subsets. We strongly recommend that you review your search strategies if you used the Journal Subset (SB) field, or limits in search strategies prior to the 2022 reload.

IM Index Medicus
OM OLDMEDLINE Citations

Do not confuse these journal subsets with the Topics subsets available on PubMed's Limits screen, which are based on different search strategies.

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SE Season [Word Indexed]
summer.se.

The Season (SE) field contains the month or season that the citation article was published.

The field usually consists of a three-character alphabetic abbreviation of the month or season.

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SH MeSH Subject Headings [Phrase Indexed]
hierarchy social.sh.
randomized controlled trial.sh.

The MeSH Subject Headings (SH) field contains the Medical Subject Headings used by indexers at the National Library of Medicine (NLM) to describe the content of an article. NLM's MeSH terms are organized in a hierarchy, or "tree" structure.

MeSH headings are entered into the index as phrases and should be searched as they appear in the NLM MeSH books or in our Tree display.

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SI Secondary Source ID [Phrase Indexed]
clinicaltrials.si.

The Secondary Source ID (SI) identifies secondary source databanks with unique identifiers of outside resources discussed in MEDLINE articles. The field is composed of the source acronym: GENBANK.

The Secondary Source ID (SI) formerly known as the Molecular Sequence (MS) field was added to Ovid MEDLINE(R) in 1988.

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SL Secondary Source Link [Phrase Indexed]
https www controlled trials com isrctn97412358.sl.
The Secondary Source Link (SL) index contains the URL to the outside resources discussed in MEDLINE articles when the Secondary Source ID is either ClinicalTrials.gov or ISRCTN. The index contains the the URL, for searching ease use the Secondary Source AN (SA) index: nct00000150.sa.
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SM Space Flight Mission [Phrase Indexed]
Aerobee 150A Project.sm.
The Space Flight Mission (SM) field provides descriptive values for each Space Flight Mission.
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SN Section [Word Indexed]
managing.sn.
The Section (SN) field contains the title of a certain section or part of a book citation. It may also contain subsections.
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SO

Source (BN, BT, BV, DP, IP, JN, PB, PG, SE, VO, YR)
accounts of chemical research.jn.
a39.pg.

The Source (SO) field includes a display of all the basic information needed to locate a record, including the full Book Edition (BN), Book Title (BT), Book Volume (BV), Journal Name (JN), the Issue/Part (IP), Page (PG), Season (SE), Volume (VO), Year (YR), and Date of Publication (DP).
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ST Status [Text Indexed]
medline.st

The Status (ST) field contains the status of the citation.

In-Data-Review records have passed the first step in quality control and will either be reissued as In-process records or go directly to PubMed-not-MEDLINE as the final record status.

In-Process records are electronically submitted and have gone through the second citation-level review.

Medline records have passed all steps in quality control and have been indexed.

Publisher - Citations recently added to PubMed via electronic submission from a publisher, and are soon to proceed to the next stage, PubMed - in process. This tag is also on citations received before late 2003 if they are from journals not indexed for MEDLINE, or from a journal that was accepted for MEDLINE after the citations' publication date. These citations bibliographic data have not been reviewed.

PubMed-not-MEDLINE records have gone through the second citation-level review, but are from non-Medline journals or precede the date a journal was selected for MEDLINE indexing but are now being submitted for inclusion.

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SY Synonyms [Word Indexed]
recessive.sy.

The Synonyms (SY) field contains a synonymous name for generic drug names that are not actual trade names.

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TC Title Comment [Word Indexed]
zou.tc.

The Title Comment (TC) field pertains to and contains citations to associated journal publications, e.g., comments, errata, retractions, or cited references. These data enable links between the record at hand and its associated citations.

This field begins with the indication of comment or correction type (see Comments (CM) fields for a full list of types) and then displays the Journal Abbreviation (JA), Date of Publication (DP), Volume (VO), Issue/Part (IP) and Page (PG).

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TI Title [Word Indexed]
zzf51.ti.
The Title (TI) field contains the English language version of a title. For documents which were not written in English, the original or transliterated title appears in a separate field, Original Title (OT).  

The title sometimes includes notes, in brackets, about the article, such as an indication that it is a letter, editorial, or comment.
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TW Text Word (AB, TI)
heart.tw.

The Text Word (TW) index in Ovid MEDLINE(R) includes Title (TI) and Abstract (AB).

In order to perform a free-text search in all of the relevant fields that contain text words appropriate for a subject search, you are advised to use the multi-purpose field (MP), e.g. heart.mp.

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UI Unique Identifier [Phrase Indexed]
10339538.ui.
9990101.ui.

The Unique Identifier (UI) field contains the PMID (PubMed identifier or PubMed unique identifier) that is the unique number assigned to each PubMed record.

PMIDs do not change over time or during processing and are never reused.

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UL Population Supplementary Concept [Phrase Indexed]
The Population Supplementary Concept (UL) field contains the Protocol Class 5 SCR terms that includes American Indian and Alaskan Native tribal names and ethnic and ethnolinguistic minority terms. The Population Supplementary Concept (UL) terms are phrase indexed.

They appear for the first time in the 2023 MeSH.

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UP Update Date [Phrase Indexed]
20170127.up.
The Update Date (UP) field contains the date the record was added to MEDLINE since the yearly reload completion. The Update Date for existing records changes with each global reload to reflect the date Ovid starts processing the reload data. The UP field appears in the format YYYYMMDD.
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UX Population Supplementary Concept [Word Indexed]
The Population Supplementary Concept Word (UX) index allows the users to retrieve single terms from the Population Supplementary Concept (UL) field.
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VB Volume Book Title [Word Indexed]
sample.vb.
The Volume Book Title (VB) field contains the volume title information of a book citation. This information displays as part of the Source (SO) field.
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VD Version Date [Phrase Indexed]
2016 04 20.vd.
The Version Date (VD) field is a new model of publishing referred to as "versioning" whereby multiple versions of the same online article are released, sometimes in quick succession and sometimes almost as soon as the original article has been published. Although the Version Date value may be different from the Date of Publication, it might be the same as Date of Publication if the new version was released later the same day. Version Date is phrase indexed.

NLM does not expect many journals will publish versions, thus the incidence of versioned citations will be small.

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VI Version ID [Phrased Indexed]
"5".vi.
Version ID (VI) field is a new model of publishing referred to as "versioning" whereby multiple versions of the same online article are released. A version is a subsequent publication of a previously published article that incorporates new data or findings using a publishing practice designed specifically for rapidly communicating scientific results. Though NLM does not expect many journals will publish versions, thus the incidence of versioned citations will be small. A version is NOT a re-publication of a previously published article that incorporates editorial changes, it is not an erratum notice, it is not a manuscript, it is not publish ahead of print, and it is not an updated article appearing years after the original. Version ID is phrase indexed.
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VO Volume [Word Indexed]
suppl.vo.
insider.vo.
The Volume (VO) field consists of the volume and issue of a serial publication. This field is usually displayed as part of the Source (SO) field.
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XM Exploded MeSH Heading [Phrase Indexed]
whales.xm.
The Exploded MeSH Heading (XM) field displays pre-exploded MeSH Headings. MeSH Subject Headings are hierarchical, with up to twelve levels of narrower terms from the top of a hierarchy. In order to retrieve a term and all of its narrower terms, a subject heading must be "exploded", that is, the subject heading and all narrower terms are "OR'd" together. OVID pre-explodes highly-posted broader terms with their narrower terms during loading. These pre-exploded MeSH Headings are displayed in the MeSH Subject Headings (SH) field.
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XS Exploded Subheading [Phrase Indexed]
tu.xs.
pd.xs.

The Exploded Subheadings (XS) field displays the two-letter codes for the pre-exploded subheadings.

Sometimes multiple MeSH Subheadings can be logically grouped together. Such related groups of subheadings are "pre-exploded" under one broad subheading. This means that all the grouped subheadings can be retrieved together by searching on the "pre-exploded" version of the broad subheading. These pre-exploded MeSH Headings are displayed in the MeSH Subject Headings (SH) field. Their complete list can be found in https://www.nlm.nih.gov/mesh/subhierarchy.html. The CAPITAL two letter codes in the left column are the Exploded Subheadings. Terms under the exploded subheading are also searched when you use the exploded subheading.

For example, the Ovid search: an.xs retrieves any records that contain the subheadings, Analysis, Blood, Cerebrospinal Fluid, Isolation and Purification or Urine.

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YR Year of Publication [Phrase Indexed]
2016.yr.
The Year of Publication (YR) field contains the year in which an article or monograph was published. Only the four digit year is contained in the index.
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Advanced Searching
You can use special search syntax listed below to combine search terms or strategically develop a search. Full documentation is provided in the Advanced Searching Techniques section of the Online Help.
Operator Syntax Search Example Sample Results
OR x or y heart attack or myocardial infarction "Role of adjunctive thrombectomy and embolic protection devices in acute myocardial infarction: a comprehensive meta-analysis of randomized trials."

The OR operator retrieves records that contain any or all of the search terms. For example, the search heart attack or myocardial infarction retrieves results that contain the terms heart attack, myocardial infarction or both terms; results are all inclusive. You can use the OR operator in both unqualified searches and searches applied to a specific field.
AND x and y blood pressure and stroke "Alcohol intake, circadian blood pressure variation, and stroke"

The AND operator retrieves only those records that include all of the search terms. For example, the search blood pressure and stroke retrieves results that contain the term blood pressure and the term stroke together in the same record; results are exclusive of records that do not contain both of these terms. You can use the AND operator in both unqualified searches and searches applied to a specific field.
NOT x not y health reform not health maintenance organizations "Financial crisis threatens US health reform."

The NOT operator retrieves records that contain the first search term and excludes the second search term. For example, the search health reform not health maintenance organizations retrieves only those records that contain the term health reform but excludes the term health maintenance organizations. In this way, you can use the NOT operator to restrict results to a specific topic.
You can use the NOT operator in both unqualified searches and searches applied to a specific field.
Adjacency (ADJ) x y blood adj pressure "Blood pressure and mortality risk on peritoneal"

The Adjacent operator (ADJ) retrieves records with search terms next to each other in that specific order. You do not need to separate search terms manually by inserting ADJ between them, because when you separate terms with a space on the command line, Ovid automatically searches for the terms adjacent to one another. For example, the search blood pressure is identical to the search blood adj pressure.
Defined Adjacency (ADJn) x ADJn y physician adj5 relationship "Changes in physician-patient relationship"

The defined adjacency operator (ADJn) retrieves records that contain search terms within a specified number (n-1) of words from each other in any order (stop-words included). To use the adjacency operator, separate your search terms with ADJ and a number from 1 to 99 as explained below:

           ADJ1     Next to each other, in any order
           ADJ2     Next to each other, in any order, up to 1 word in between
           ADJ3     Next to each other, in any order, up to 2 words in between
           ADJ99   Next to each other, in any order, up to 98 words in between

For example, the search physician adj5 relationship retrieves records that contain the words physician and relationship with a maximum of four words in between in either direction. This particular search retrieves records containing such phrases as physician patient relationship, patient physician relationship, or relationship between cancer patient and physician.
Please note Ovid’s order of operation handles terms within parentheses first. Therefore it is recommended to apply the ADJn operator in one-on-one operations to avoid missing out on results. E.g. stroke adj4 (blood pressure or high blood pressure) could potentially miss out on some combinations of stroke with high blood pressure. The optimum way to execute this on Ovid is: (stroke adj4 blood pressure) OR (stroke adj4 high blood pressure).
Frequency (FREQ) x.ab./FREQ=n blood.ab./freq=5 "Is the accuracy of blood pressure measuring devices underestimated at increasing blood pressure levels?"

The frequency operator (FREQ) lets you specify a threshold of occurrence of a term in the records retrieved from your search. Records containing your search term are retrieved only if the term occurs at least the specified (n) number of times. In general, records that contain many instances of your search term are more relevant than records that contain fewer instances. The frequency operator is particularly useful when searching a text field, such as Abstract or Full Text, for a common word or phrase.

The frequency operator cannot be applied to multiple fields (e.g. .ti,ab.) or fields that are composed out of other fields such as the Source field (.so.).

Unlimited Truncation ($) x$ disease$ "identify genes responsible for diseases and traits"

Unlimited truncation retrieves all possible suffix variations of the root word indicated. To apply unlimited truncation to a term, type the root word or phrase followed by either of the truncation characters: $ (dollar sign) or * (asterisk). For example, in the truncated search disease*, Ovid retrieves the word disease as well as the words diseases, diseased, and more.
Limited Truncation ($) x$n dog$1 "renal function in healthy dogs"

Limited truncation specifies a maximum number of characters that may follow the root word or phrase. For example, the truncated search dog$1 retrieves results with the words dog and dogs; but it does not retrieve results with the word dogma.
Mandated Wildcard (#) xx#y wom#n "serum homocysteine levels in postmenopausal women"

Searching with a mandated wildcard retrieves all possible variations of a word in which the wildcard is present in the specified place. You can use it at the end of a term to limit results to only those that contain the word plus the mandated character. For example, the search dog# retrieves results that contain the word dogs, but not those that contain the word dog, effectively limiting results to only those that contain the plural form of the word. The mandated wild card character (#) is also useful for retrieving specialized plural forms of a word. For example, the search wom#n retrieves results that contain both woman and women. You can use multiple wild cards in a single query word.
Optional Wildcard (?) xx?y colo?r "Hair changes. Age has effect on color, thickness."

The optional wild card character (?) can be used within or at the end of a search term to substitute for one or no characters. This wild card is useful for retrieving documents with British and American word variants since it specifies that you want retrieval whether or not the extra character is present. For example, the optional wild card search colo?r retrieves results that contain the words color or colour. You can use multiple wild cards in a single query word.
Literal String ("") "x / y"

"go/no-go"

"Single trial-based prediction of a go/no-go decision in monkey superior colliculus"

"n"

"3".vo

"Nature Clinical Practice Cardiovascular Medicine. 3(12):689-92, 2006 Dec."

Quotation marks can be used to retrieve records that contain literal strings, when the string includes special characters, such as a forward slash (/).

Quotation marks can also be used to retrieve records that contain numbers that may otherwise be confused for earlier searches. In the example, a search for 3.vo would limit the string from your third search in your search history to the volume field. By including the number in quotation marks, the search will retrieve documents with a 3 in the volume number.

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Stopwords
The Ovid search engine applies so called "run-time stopword processing". This means the search engine on the fly ignores the stopwords: and, as, for, from, is, of, that, the, this, to, was, were.

Therefore a search: at risk for diabetes.ti will also find: at risk of diabetes. The distance of one word in between is kept, but the stopword "for" is ignored.

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Limits
The following limits are available for this database. See Database Limits in the Ovid Online Help for details on applying limits.

Limit

Syntax
Abstracts Sentence Syntax: limit 1 to abstracts
Command Syntax: ..l/ ab=y
A limit to Abstracts restricts retrieval to documents which include an abstract. Over 50% of Ovid MEDLINE(R) records after 1975 contain abstracts. All abstracts included in Ovid MEDLINE(R) are in English and were written by the author(s) of the original article.
Age Groups Sentence Syntax: limit 1 to infant
limit 1 to adult
limit 1 to middle aged
A limit by Age Group restricts retrieval by any of the age groups indexed by NLM. Since only human age groups are indexed, this limit will also restrict retrieval to human subjects. If you choose this option you will be presented with a list of age groups from which to select.
Animals Sentence Syntax: limit 1 to animals

A limit to Animals restricts retrieval to documents which are primarily about animal subjects. It will retain articles about both human and animal subjects. Consider also the Limit to Animal Type, which will allow you to select from a list of common experimental research animals.

Animal Types Sentence Syntax: limit 1 to cats
limit 1 to rabbits
A limit by Animal Type restricts retrieval to any of the basic animal types indexed by NLM. If you choose this option you will be presented with a short alphabetical list of some common research animal types from which to select. Consider also the Limit to Animal, which restricts retrieval to documents which are about any animal subject.
Books and Documents Sentence Syntax:

The Books and Documents limit captures book records provided by the NCBI Bookshelf database and indexed in PubMed.

Clinical Queries Sentence Syntax: limit 1 to "Therapy (sensitivity)"
   

Limiting to Clinical Queries will restrict retrieval clinically sound studies. There are nine categories provided, and the emphasis may be Sensitive (i.e., most relevant articles but probably some less relevant ones), Specific (i.e., mostly relevant articles but probably omitting a few), or Optimized (i.e., the combination of terms that optimizes the trade-off between sensitivity and specificity).

These filters, based on the work of R. Brian Haynes MD, PhD et al. of the Health Information Research Unit (HIRU) at McMaster University, are intended for clinicians. A detailed explanation of the strategies behind these limits can be found at http://hiru.mcmaster.ca/hiru/HIRU_Hedges_MEDLINE_Strategies.aspx.

Clinically Useful Journals (JMLA July 2023) Sentence Syntax: limit 1 to "Clinically Useful Journals (JMLA July 2023)"
Limits to 241 selected journals, using the search logic from Appendix H as published in: Klein-Fedyshin M, Ketchum AM. PubMed’s Core Clinical Journals Filter: Redesigned for Contemporary Clinical impact and Utility.
J Med Libr Assoc. 2023 Jul;111(3) DOI:
https://doi.org/10.5195/jmla.2023.1631

Core Clinical Journals (AIM: Discontinued in 2020) Sentence Syntax: limit 1 to "Core Clinical Journals (AIM: Discontinued in 2020)"
A limit to Core Clinical Journals (AIM: Discontinued in 2020) will restrict retrieval to the 119 core clinical journals which comprise the Abridged Index Medicus collection.

This is a good way to limit your retrieval to journals more commonly found in hospital and medical library collections.

Dietary Supplements Sentence Syntax: limit 1 to dietary Supplements
A limit to Dietary Supplements is designed to limit search results to citations from a broad spectrum of dietary supplement literature. This strategy was based on PubMed's Dietary Supplements subset limit.
English Language Sentence Syntax: limit 1 to english
Command Syntax: ..l/1 en=y
A limit to English restricts retrieval to articles which are written in the English language. Foreign language articles with English abstracts will be eliminated by a limit to English.
Female Sentence Syntax: limit 1 to female
A limit to Female restricts retrieval to documents which are about females, either human or animal.
Full Text Sentence Syntax: limit 1 to full text
A limit to Full Text restricts retrieval to those citations for which there is a full text link. Both Ovid full text and external full text are included in this limit.
Humans Sentence Syntax: limit 1 to humans
Command Syntax: ..l/1 hu=y

A limit to Humans restricts retrieval to articles which are about human subjects. If you limit by Age Group you do not need to use this limit.

Journal Subsets Sentence Syntax: limit 1 to "Dentistry Journals"
Command Syntax: ..l/1 sb=Dentistry Journals
You can restrict your retrieval to any of these subsets by a limit to journal subset. If you choose this option you will be presented with an alphabetical list of Journal Subsets from which to select.

Please note the NLM has discontinued their Journal Subset (SB) limits for MEDLINE/PubMed with the 2022 reload, with the exception of "index medicus.sb." and "oldmedline citations.sb.". To ensure existing Ovid search strategies and alerts don't break, Ovid replaced them with new limits based on NLM Catalog searches, using matching MeSH terms and title words to create new lists of titles for the below journal subset limits. The new limits and the ensuing results don't compare to the old NLM versions, so we strongly recommend that you review your search strategies if you used the Journal Subset (SB) limits in search strategies prior to the 2022 reload.

Name of limit: Keywords used for NLM Catalog search
AIDS/HIV Journals Hiv, Hiv Infections, Acquired Immunodeficiency Syndrome, Aids, Hiv
Behavioral Sciences Journals Behavioral Sciences
Bioethics Journals Bioethics, Bioethic
Biotechnology Journals Biotechnology, Biotech
Cardiology Journals Cardiology
Clinically Useful Journals (JMLA July 2023) Using the list of Journals: https://jmla.pitt.edu/ojs/jmla/article/view/1631/2209
Communication Disorders Journals Consumer Health Information, Health Education, Consumer Health, Popular Work Publication Type Health
Consumer Health / Health Education Journals Communication Disorder, Communication Disorder, Language Disorder, Agraphia, Anomia, Dyslexia, Alexia, Language Disorder, Speech Disorder OR Aphasia, Articulation Disorder, Dysarthria, Echolalia, Mutism, Stuttering, Learning Disabil, Dyscalculia, Dyslexia
Core Clinical Journals (AIM: Discontinued in 2020) Using list of Journals: https://www.nlm.nih.gov/bsd/aim.html
Dentistry Journals Dentistry, Dentistry, Dental
Epidemiology & Infectious Diseases Journals Epidemiology, Communicable Diseases
Genetics or Genomics Journals Genetics, Genomics
Health Administration Journals Health Services Administration, Health Administration, Services, Service
Health Technology Assessment Journals Technology Assessment, Biomedical, Technology Health, Assessment
History of Medicine Journals History Of Medicine, History Medicine
HTA and Computing Methodology Journals Computing Methodologies, Technology Assessment, Biomedical
Index Medicus Journals Using the IM.SB indexing for MEDLINE
International Journals Internationality, Global, International
Nursing Journals Nursing
OLDMEDLINE Citations Using the OM.SB indexing for MEDLINE
Pharmacology Journals Pharmacology
Population Information Citations Population Characteristics, Population
Public Health Journals Public Health
Radiology Journals Radiology, Radiography
Reproduction Journals Reproduction, Fertility
Space and Aerospace Medicine Journals AEROSPACE MEDICINE, Space Flight, Aeronautics, Astronautics, NASA, Space Research, Space Science, Space Sciences
Surgery Journals Surgical Procedures, Operative, General Surgery
Languages Sentence Syntax: limit 1 to french
Command Syntax: ..l/1 lg=fre
A limit to Language restricts retrieval to any of the languages indexed by NLM. If you choose this option you will be presented with an alphabetical list of languages from which to select.
Latest Update Sentence Syntax: limit 1 to latest update
New documents are added to the Ovid MEDLINE(R) database at regular intervals. A limit to latest update restricts retrieval to documents which were most recently added to the database.

Local Holdings

Sentence Syntax: limit 1 to local holdings
  A limit to local holdings will restrict retrieval to documents from journals held in your local library or library system.

If your System Administrator has created any special messages about a journal's availability, this message will display with the document in the Local Holdings (LH) field.

Male Sentence Syntax: limit 1 to male
A limit to Male restricts retrieval to documents which are about males, either human or animal.
No Language Specified Sentence Syntax: limit 1 to no language specified
A limit to No Language Specified will restrict retrieval to articles without specific language. All foreign articles including English abstracts will be eliminated by this limit.
Ovid Full Text Available Sentence Syntax: limit 1 to Ovid Full Text Available
A limit to Ovid Full Text Available restricts retrieval to those citations for which an Ovid full text link is available. When viewing a citation with full text available use the LINK button to display the full text.
Pharmacologic Actions Sentence Syntax: limit 1 to pharmacologic actions
A limit to Pharmacologic Actions will restrict your retrieval to a broad category of chemical actions and uses that result in the prevention, treatment, cure or diagnosis of disease. Included here are drugs and chemicals that act by altering normal body functions, such as the REPRODUCTIVE CONTROL AGENTS and ANESTHETICS. Effects of chemicals on the environment are also included.
Publication Types Sentence Syntax: limit 1 to clinical trial
limit 1 to clinical trial, all
limit 1 to dataset
limit 1 to journal article
limit 1 to observational study
limit 1 to pragmatic clinical trial
limit 1 to review
limit 1 to systematic reviews
limit 1 to preprint
A limit by Publication Type restricts retrieval by any of the over forty publication types indexed by NLM, including classifications such as "bibliography," "classical article," "clinical trial," etc.
Publication Year Sentence Syntax: limit 1 to yr=2006
Command Syntax: ..l/1 yr=2006
You can restrict retrieval to any of the years which this Ovid MEDLINE(R) segment covers. If you choose this option you will be prompted to enter the desired year; the format is 4 digits: "1989" or a range: "1994-1995."
Range Limits Sentence Syntax: limit 1 to dt=20191201-20201231
Command Syntax: ..l/1 dt=20191201-20201231
20191201:20201231.(dt).
Range limits are available for the DT, DA, ED, EP, EZ, RD, and UP fields. These limits are not listed in the drop-down menu, however they can be run straight from the command line in Advanced Search mode. These date fields are formatted YYYYMMDD, and below are examples how to apply them as date-range limits on Ovid:

limit 1 to ed=20181116-20181217
limit 1 to rd=20181221-20181231
limit 1 to up=20181211-20181231
limit 1 to ep=20181001-20181115
limit 1 to dt=20181001-20191001
limit 1 to da=20160101-20160422
limit 1 to ez=20150101-20150218

Remove Preprint Records Sentence Syntax: limit 1 to "remove preprint records"
This limit allows to remove preprint records from the search results. Preprints are preliminary reports of work that have not been certified by peer review.
Review Articles Sentence Syntax: limit 1 to "review articles"
A limit to Review Articles restricts retrieval to articles which are reviews of a subject. For NLM databases this includes all review types: Review Literature; Review of Reported Cases; Review, Academic; Review, Multicase; and Review, Tutorial.

Special Ovid Filters for MEDLINE

Sentence Syntax: limit 1 to Adverse Effects - focussed
limit 2 to Children - focussed
 

You can use Special Ovid Filters to restrict retrieval to a pre-defined set of records, populated by a special Ovid search strategy for that topic. As the results sets for these filters are created with every database update, the results display quickly. Ovid filters are "AND" combined with the search line you are trying to limit, unless stated otherwise (e.g. humans only).

Each of the search hedges below are based on publicly available filters that have been reviewed, translated, and improved by Ovid expert searchers. While these filters aren't validated by Ovid, we provide the full transcript for each filter below and we have placed a reference for each filter where applicable. You may want to review the underlying terms and modify them as necessary.

Ovid welcomes your suggestions to enhance the filters. Please contact [email protected].

Adverse effects

exp "drug-related side effects and adverse reactions"/or adverse.ti,ab, kf. or side effect?.ti,ab,kf. or adverse effects.fs. or exp drug overdose/ or overdos*.ti,ab,kf. or exp drug misuse/ or misus*.ti,ab,kf. or exp substance-related disorders/ or abus*.ti,ab,kf. or exp pregnancy/ or pregnan*.ti,ab,kf. or exp pregnancy complications/ or exp lactation/ or exp lactation disorders/ or exp breast feeding/ or (exp milk, human/ and exp secretion/) or exp fertility/ or exp infertility/ or exp reproduction/ or exp fetus/ or exp embryonic structures/ or terat*.ti,ab,kf. or drug efficacy.ti,ab,kf. or therapeutic efficacy.ti,ab,kf. or drug withdrawal.ti,ab, kf. or exp medication errors/ or exp death/ or death*.ti,ab,kf. or fatal*.ti,ab,kf. or exp drug interactions/ or exp carcinogens/ or carcinogen*.ti,ab,kf. or mutagen*.ti,ab,kf. or exp "off-label use"/ or exp occupational exposure/ or toxicity.fs. or toxic*.ti,ab,kf. or pharmacotox*.ti,ab,kf. or neurotox*.ti,ab,kf. or cardiotox*.ti,ab,kf. or nephrotox*.ti,ab,kf. or immunotox*.ti,ab,kf. or hepatotox*.ti,ab,kf. or cytotox*.ti,ab,kf. or immunocytotox*.ti,ab,kf. or intoxicat*.ti,ab,kf. or exp "congenital, hereditary, and neonatal diseases and abnormalities"/ or drug treatment failure.ti,ab,kf. or drug toxicity.ti,ab,kf. or exp case reports/ or case report?.ti,ab,kf. or exp environmental exposure/ or treatment contraindication.ti,ab,kf. or exp contraindications, drug/ or exp "wounds and injuries"/ or suicid*.ti,ab,kf. or exp poisoning/ or poisoning.fs. or exp drug tolerance/ or exp treatment failure/ or exp drug resistance/ or exp substance-related disorders/

Last reviewed 13 February 2023. This is based on guidelines provided by the European Medicines Agency (EMA), monitoring of medical literature and the entry of relevant information into the EudraVigilance database by the EMA. https://www.ema.europa.eu/documents/other/monitoring-medical-literature-entry-relevant-information-eudravigilance-database-european-medicines_en.pdf

 
Adverse effects - Focussed

exp *"drug-related side effects and adverse reactions"/or adverse.ti,kf. or side effect?.ti,kf. or adverse effects.fs. or exp *drug overdose/ or overdos*.ti,kf. or exp *drug misuse/ or misus*.ti,kf. or exp *substance- related disorders/ or abus*.ti,kf. or exp *pregnancy/ or pregnan*.ti,kf. or exp *pregnancy complications/ or exp *lactation/ or exp *lactation disorders/ or exp *breast feeding/ or (exp milk, human/ and exp secretion/) or exp *fertility/ or exp *infertility/ or exp *reproduction/ or exp *fetus/ or *exp embryonic structures/ or terat*.ti,kf. or drug efficacy.ti,kf. or therapeutic efficacy.ti,kf. or drug withdrawal.ti,kf. or exp *medication errors/ or exp *death/ or death*.ti,kf. or fatal*.ti,kf. or exp *drug interactions/ or *exp carcinogens/ or carcinogen*.ti,kf. or mutagen*.ti,kf. or exp *"off-label use"/ or *exp occupational exposure/ or toxicity.fs. or toxic*.ti,kf. or pharmacotox*.ti,kf. or neurotox*.ti,kf. or cardiotox*.ti,kf. or nephrotox*.ti,kf. or immunotox*.ti,kf. or hepatotox*.ti,kf. or cytotox*.ti,kf. or immunocytotox*.ti,kf. or intoxicat*.ti,kf. or *exp "congenital, hereditary, and neonatal diseases and abnormalities"/ or drug treatment failure.ti,kf. or drug toxicity.ti,kf. or case reports/ or case report?.ti,kf. or exp *environmental exposure/ or treatment contraindication.ti,kf. or exp *contraindications, drug/ or exp *"wounds and injuries"/ or suicid*.ti,kf. or exp *poisoning/ or poisoning.fs. or exp *drug tolerance/ or exp *treatment failure/ or exp *drug resistance/ or exp *substance-related disorders/

Last reviewed 13 February 2023. This is similar to the filter above but uses focussed subject headings and only uses Title and Keywords for the free-text component of the strategy.

 
Adverse effects - Medical devices

complicat*.ti,ab. OR ae.fs. OR safe*.ti,ab. OR exp postoperative complications/ OR failure*.ti,ab. OR adverse.ti,ab. OR co.fs. OR failed.ti,ab. OR exp equipment failure/ OR removal.ti,ab. OR equipment safety/ OR problem*.ti,ab. OR side effect*.ti,ab. OR Harmful.ti,ab. OR Tolerated.ti,ab. OR loosen*.ti,ab. OR Intraoperative Complications/ OR migration.ti,ab. OR breakag*.ti,ab. OR discomfort.ti,ab. OR displacement.ti,ab. OR (detrimental adj2 effect*).ti,ab. OR untoward effects.ti,ab.

Last reviewed 13 February 2023.This filter is based on: Golder S, Farrah K, Mierzwinski-Urban M, Wright K, Loke YK. The development of search filters for adverse effects of medical devices in MEDLINE and Embase. Health Info Libr J 2019 Jun 11. https://doi.org/10.1111/hir.12260.

 
Adverse effects - Surgical interventions

complication*.ti,ab. OR ae.fs. OR safe*.ti,ab. OR co.fs. OR postoperative complications/

Last reviewed 13 February 2023.This filter is based on: Golder S, Wright K, Loke YK. The development of search filters for adverse effects of surgical interventions in MEDLINE and Embase. Health Info Libr J 2018 Mar 31. https://doi.org/10.1111/hir.12213.

 
Children

Includes records about neonate and birth to about 18 years.

exp adolescent/ or exp child/ or exp infant/ or (infant disease* or childhood disease*).ti,ab,kf. or (adolescen* or babies or baby or boy? or boyfriend or boyhood or child* or girl? or infant* or juvenil* or kid? or minors or minors* or neonat* or neonat* or newborn* or new-born* or paediatric* or peadiatric* or pediatric* or perinat* or preschool* or puber* or pubescen* or school* or teen* or toddler? or underage? or under-age? or youth*).ti,ab,kf,hw.

Last reviewed 13 February 2023. This Paediatrics filter is based on the Improved "Cochrane Childhood Cancer Group" Child filter published here: https://doi.org/10.1016/j.jpeds.2012.09.012

 
Children - Focussed

exp *adolescent/ or exp *child/ or exp *infant/ or (infant disease* or childhood disease*).ti,kf. or (adolescen* or babies or baby or boy? or boyfriend or boyhood or child* or girl? or infant* or juvenil* or kid? or minors or minors* or neonat* or neonat* or newborn* or new-born* or paediatric* or peadiatric* or pediatric* or perinat* or preschool* or puber* or pubescen* or school* or teen* or toddler? or underage? or under-age? or youth*).ti,kf.

Last reviewed 13 February 2023. This filter is similar to the filter above but uses focussed subject headings and only uses Title and Keywords for the free-text component of the strategy.

 
Covid - 19

exp Coronavirus/

exp Coronavirus Infections/

(coronavirus* or anti-corona* or corona virus* or OC43 or NL63 or 229E or HKU1 or HCoV* or ncov* or anti-ncov* or anti-cov* or covid* or anti-covid* or sars-cov* or anti-sars* or sarscov* or Sars-coronavirus* or Severe Acute Respiratory Syndrome Coronavirus* or ((kawasaki or pe?diatric or child*) and (inflammatory adj1 multisystem syndrome)) or "PIMS-TS" or "Kawa-COVID-19" or "MIS-C" or "multisystem inflammatory syndrome in children" or pediatric multisystem inflammatory disease).mp.

(or/1-3) and 20190101:20301231.(dt). [this set is the sensitive/broad part of the search]

4 not (SARS or SARS-CoV or MERS or MERS-CoV or Middle East respiratory syndrome or camel* or dromedar* or equine or coronary or coronal or covidence* or covidien or influenza virus or HIV or bovine or calves or TGEV or feline or porcine or BCoV or PED or PEDV or PDCoV or FIPV or FCoV or SADS-CoV or canine or CCov or zoonotic or avian influenza or H1N1 or H5N1 or H5N6 or IBV or murine corona*).mp. [line 5 removes SARS, MERS and veterinary noise from the sensitive/broad search results]

((pneumonia or covid* or coronavirus* or corona virus* or ncov* or 2019-ncov or sars*).mp. or exp pneumonia/) and (Wuhan or Hubei or Huanan).mp. [Early articles about the outbreak]

exp covid-19/ or (2019-ncov or ncov19 or ncov-19 or 2019-novel CoV or sars-cov2 or sars-cov-2 or sarscov2 or sarscov-2 or SARS-2-nCoV or SARS-2-Cov or SARS-COV-19 or Sars-coronavirus2 or Sars-coronavirus-2 or SARS 2 coronavirus* or Severe Acute Respiratory Syndrome-CoV-2 or SARS-like coronavirus* or coronavirus-19 or covid19 or covid-19 or covid 2019 or ((novel or new or nouveau) adj2 (CoV or nCoV or covid or coronavirus* or corona virus or Pandemi*2)) or ((covid or covid19 or covid-19 or SARS-CoV-2) and pandemic*2) or (coronavirus* and pneumonia)).mp. [specific to Covid-19, Covid pneumonia, Covid pandemic]

(COVID-19 or SARS-CoV-2).rx,px,ox,rn. or (COVID-19 or COVID-19 serotherapy or ORF7b protein, SARS-CoV-2 or ORF6 protein, SARS-CoV-2 or ORF8 protein, SARS-CoV-2 or pediatric multisystem inflammatory disease, COVID-19 related or envelope protein, SARS-CoV-2 or ORF7a protein, SARS-CoV-2 or spike protein, SARS-CoV-2 or ORF3a protein, SARS-CoV-2 or COVID-19 drug treatment or severe acute respiratory syndrome coronavirus 2 or membrane protein, SARS-CoV-2 or ORF1ab polyprotein, SARS-CoV-2 or nucleocapsid protein, Coronavirus or COVID-19 vaccine or COVID-19 diagnostic testing).os,ps,rn,rs. [Relevant Suppl. Concepts listed in MeSH 2021 Browser]

44 and (exp Vaccination/ or exp Vaccines/ or "vaccin*".rn,ox,px,rx. or vaccin*.mp. or exp antibodies/ or antibodies.mp. or ("AAVCOVID" or "Ad5-nCoV" or "AdCOVID" or "AdimrSC-2f" or "AG0301-COVID19" or "ARCT-021" OR "LUNAR-COV19" or "AZD1222" or "Bacillus Calmette-Guerin vaccine" or BCG or "bacTRL-Spike" or "BBIBP-CorV" or "BNT162" or "ChAd-SARS-CoV-2-S" or "CoronaVac" or "COVAX-19" or "Covaxin" or "CVnCoV" or "DelNS1-2019-nCoV-RBD-OPT1" or "EpiVacCorona" or "GRAd-COV2" or "GX-19" or "HaloVax" or "HDT-301" or "INO-4800" or "JNJ-78436735" OR "Ad26.COV2.S" or "LineaDNA" or "LNP-nCoVsaRNA" or "Mechanism" or "Mechanism" or "Mechanism" or "Mechanism" or "Mechanism" or "mRNA-1273" or "MRT5500" or "NVX-CoV2373" or "PittCoVacc" or "SCB-2019" or "Sputnik V" or "T-COVIDTM" or "UB-612" or "UQ-CSL V451" or "V590" or "V591" or "VIR-7831" or "VXA-CoV2-1" or "ZyCoV-D").mp. or (mRNA vaccine$ or messenger RNA vaccine$ or AstraZeneca$1 or Janssen$s or Moderna$1 or Novavax$1 or Pfizer$1 or BioNTech$1).mp.) [Line to add everything related to Vaccines and coronavirus]

4 and (Chloroquine or hydroxychloroquine or convalescent plasma or Remdesivir or Veklury or azithromycin or bamlanivimab or "LY CoV555" or corticosteroids or glucocorticoids or "vitamin C" or lopinavir or ritonavir or ivermectin or Tocilizumab or Favipiravir or dexamethasone HIV protease inhibitors).mp. [specific to Covid specific drug treatment]

("33692505" or "33838627" or "33857053" or "33631632" or "33794172" or "34133435" or "33977575" or "33797807" or "32998780" or "32962779" or "32953429" or "32839969" or "32829731" or "32826274" or "32775953" or "32775948" or "32775945" or "32407043" or "32119409" or "32172715" or "33037657" or "32492200" or "32185863" or "33063036" or "32221976" or "32495994" or "32240549" or "32405099" or "32648633" or "32463935" or "32243299" or "32416016" or "33134955" or "33013067" or "32878290" or "32837399" or "32716821" or "32489438" or "32406056" or "32396977" or "32309248" or "32265186" or "32253187" or "32250493" or "32239781" or "32237249" or "32176889" or "32152148" or "32140676" or "32053580" or "32246897" or "32428286" or "32750178" or "32510470" or "32417321" or "32334003" or "33077677" or "32403202" or "32502292" or "32896006" or "33125767" or "32822920" or "32445255" or "32943452" or "32683439" or "32692998" or "32439468" or "32299207" or "32829902" or "32205350" or "32277065" or "32179788" or "32152361" or "32426074" or "32127714" or "33010706" or "32243951" or "32188729" or "32239757" or "32267344" or "32020111" or "32955802" or "32588590" or "32491981" or "32243118" or "32240632" or "32240583" or "32233030" or "32213260" or "32188728" or "32088947" or "32047315" or "31917786" or "32970917" or "32648633" or "32416016").ui. [Selected Articles not captured by this hedge when updated on 25 August 2021]

or/5-11 [Lines 5 to 11 are specific/relevant to the Covid-19 outbreak]

12 and 20191201:20301231.(dt). [only include records created for PubMed/MEDLINE from 1 December 2019 onwards]

Last reviewed 13 February 2023. This search is optimized to achieve sensitivity (through lines 1-5) and specificity (lines 6-12). We remove unwanted records (noise) in line 5.

To load the above filter line by line to an Ovid search session please use this shared search history link: https://ovidsp.ovid.com/ovidweb.cgi?T=JS&NEWS=N&PAGE=main&SHAREDSEARCHID=2YFWeccISgqTzPSlsK63Liil30JnLEaxas6pIYnRGUpVAzv43WkIgIYiWcY3ml3nE .

Full documentation is available from the Authors: Ovid staff: Michelle Volesko Brewer, health sciences librarian and Pieter van der Houwen, product manager.

Enormous appreciation for the clinical consultation of this search by: Elaine Larson, RN, PhD, FAAN, CIC, Anna C. Maxwell Professor Emerita and Special Lecturer, School of Nursing, Professor Emerita of Epidemiology, Mailman School of Public Health, Columbia University, Scholar in Residence, New York Academy of Medicine and former editor, American Journal of Infection Control.

For questions contact: [email protected]

 
Elderly

exp aged/ or exp geriatrics/ or exp geriatric psychiatry/ or exp geriatric nursing/ or exp *geriatric psychiatry/ or exp *dental care for aged/ or exp *health services for the aged/ or (elder* or eldest or frail* or geriatri* or old age* or oldest old* or senior* or senium or very old* or septuagenarian* or octagenarian* or octogenarian* or nonagenarian* or centarian* or centenarian* or supercentenarian* or older people or older subject* or older patient* or older age* or older adult* or older man or older men or older male* or older woman or older women or older female* or older population* or older person*).ti,ab,kf.

Last reviewed 13 February 2023. This filter is based on the "Aged" filter from the Dutch Library Association: https://blocks.bmi-online.nl/catalog/7.

 
Elderly - Focussed

exp *aged/ or exp *geriatrics/ or exp *geriatric psychiatry/ or exp *geriatric nursing/ or exp *geriatric psychiatry/ or exp *dental care for aged/ or exp *health services for the aged/ or (elder* or eldest or frail* or geriatri* or old age* or oldest old* or senior* or senium or very old* or septuagenarian* or octagenarian* or octogenarian* or nonagenarian* or centarian* or centenarian* or supercentenarian* or older people or older subject* or older patient* or older age* or older adult* or older man or older men or older male* or older woman or older women or older female* or older population* or older person*).ti,kf.

Last reviewed 13 February 2023. This filter is similar to the filter above but uses focussed subject headings and only uses Title and Keywords for the free-text component of the strategy.

 
Humans only (removes records about animals)

NOT ((exp animal/ or exp invertebrate/ or animal experiment/ or animal model/ or exp plant/ or exp fungus/) not exp human/)

Last reviewed 13 February 2023. This filter is based on Ovid best practices. Most Ovid filters are "AND" combined with the line that is being limited. This filter is "NOT" combined with the search line that is being limited.

 
Pregnancy - Wide

exp pregnancy/ or exp pregnancy complications/ or exp maternal health services/ or exp fetus/ or exp fetal therapies/ or exp fetal monitoring/ or exp perinatal care/ or exp labor pain or exp analgesia, obstetrical/ or exp anesthesia, obstetrical/ or exp obstetric surgical procedures/ or exp infant, newborn/ or exp postpartum period/ or exp breast feeding/ or exp prenatal diagnosis/ or exp obstetrics/ or exp prenatal education/ or (breast-feeding education or parturition or ante natal or antenatal* or pre natal* or prenatal* or puerper* or postnatal* or postpartum or post partum or post natal* or peripartum or peri partum or prepregnancy or pre pregnancy or preconception* or pre conception* or periconception* or peri conception* or ((preterm or premature) and (labor or labour)) or eclamp* or preeclamp* or pre eclamp* or amniocentes* or chorion* vill* or breastfe* or breast fe* or lactation* or cesarean or caesarean or cesarian or caesarian or cesarien or caesarien or newborn* or new born* or tocoly* or fetal or foetal or fetus or foetus or miscarriage* or pregnancy or pregnancies or pregnant).ti,ab,kf.

Last reviewed 13 February 2023. Based on the Search strategy from the Cochrane Pregnancy and Childbirth Group: Appendix 2, Embase-Ovid: https://www.ncbi.nlm.nih.gov/books/NBK379828/

 
Pregnancy - Focussed

exp *pregnancy/ or exp *pregnancy complications/ or exp *maternal health services/ or exp *fetus/ or exp *fetal therapies/ or exp *fetal monitoring/ or exp *perinatal care/ or exp *labor pain or exp *analgesia, obstetrical/ or exp *anesthesia, obstetrical/ or exp *obstetric surgical procedures/ or exp *infant, newborn/ or exp *postpartum period/ or exp *breast feeding/ or exp *prenatal diagnosis/ or exp *obstetrics/ or exp *prenatal education/ or (breast-feeding education or parturition or ante natal or antenatal* or pre natal* or prenatal* or puerper* or postnatal* or postpartum or post partum or post natal* or peripartum or peri partum or prepregnancy or pre pregnancy or preconception* or pre conception* or periconception* or peri conception* or ((preterm or premature) and (labor or labour)) or eclamp* or preeclamp* or pre eclamp* or amniocentes* or chorion* vill* or breastfe* or breast fe* or lactation* or cesarean or caesarean or cesarian or caesarian or cesarien or caesarien or newborn* or new born* or tocoly* or fetal or foetal or fetus or foetus or miscarriage* or pregnancy or pregnancies or pregnant).ti,kf.

Last reviewed 13 February 2023. This is similar to the filter above but uses focussed subject headings and only uses Title and Keywords for the free-text component of the strategy.

Status Sentence Syntax: limit 1 to MEDLINE
Limiting to one of the five Status availble will restrict your results to those records containing that status according to the quality control step assigned by NLM.

In Data Review Publisher
In Process PubMed Not MEDLINE
MEDLINE  
Subject Subsets Sentence Syntax: limit 1 to Dietary Supplements
limit 1 to Veterinary Science
limit 1 to toxicology

Limiting to Subject Subsets will restrict retrieval to the specific subject chosen. These Subject Subset limits are based on the Subset limits in PubMed. If you choose this option you will be presented with an alphabetical list of Subject Subsets to choose from.

Structured Abstracts Sentence Syntax: limit 1 to Structured Abstracts

A limit to Structured Abstracts will restrict retrieval to citations with distinct labelled sections in the abstract (e.g., Introduction, Methods, Results, Discussion) for rapid comprehension.

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Subject Subset
Ovid MEDLINE includes the following limits based on PubMed's subject subsets. For a detailed explanation of the differences between these limits and the PubMed strategies, see Ovid MEDLINE Subject Limits Overview.
AIDS Sentence Syntax: limit 1 to AIDS
A limit to AIDS restricts retrieval to the area of AIDS. This strategy was based on PubMed's AIDS subset limit, PubMed AIDS.
Bioethics Sentence Syntax: limit 1 to bioethics
A limit to Bioethics restricts retrieval to the area of bioethics. This strategy was based on PubMed's Bioethics subset limit, PubMed Bioethics.
Cancer Sentence Syntax: limit 1 to cancer
A limit to Cancer restricts retrieval to the area of cancer. This strategy was based on PubMed's Cancer subset limit, PubMed Cancer.
Complementary Medicine Sentence Syntax: limit 1 to complementary medicine
A limit to Complementary Medicine restricts retrieval to the area of complementary and alternative medicine. This strategy was based on PubMed's Complementary Medicine subset limit, PubMed Complementary Medicine.
Dietary Supplements Sentence Syntax: limit 1 to dietary supplements
A limit to Dietary Supplements restricts retrieval to documents on the area of dietary supplements. This strategy was based on PubMed's Dietary Supplements subset limit, PubMed Dietary Supplements.
History of Medicine Sentence Syntax: limit 1 to history of medicine
A limit to History of Medicine restricts retrieval to documents on the history of medicine. This strategy was based on PubMed's History of Medicine subset limit, PubMed History of Medicine.
Space Life Sciences Sentence Syntax: limit 1 to space life sciences
A limit to Space Life Sciences restricts retrieval to citations of interest to those working in the field of space life sciences research. This strategy was based on PubMed's Space Life Sciences subset limit, PubMed Space Life Sciences.
Systematic Reviews Sentence Syntax: limit 1 to systematic reviews
A limit to Systematic Reviews restricts retrieval to citations in the area of systematic reviews. This strategy was based on PubMed's Systematic Reviews subset limit, PubMed Systematic Reviews.
Toxicology Sentence Syntax: limit 1 to toxicology
A limit to Toxicology restricts retrieval to the area of toxicology. This strategy was based on PubMed's Toxicology subset limit, PubMed Toxicology.
Veterinary Science Sentence Syntax: limit 1 to veterinary science
A limit to Veterinary Science restricts retrieval to documents on the area of Veterinary Science. This strategy was based on PubMed's Veterinary Science subset limit, PubMed Veterinary Science.
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Clinical Query Limits

Ovid MEDLINE also offers limits to Clinical Queries. These limits restrict retrieval to clinically sound studies. There are nine categories provided, and the emphasis may be Sensitive (as in most relevant articles but probably some less relevant ones), Specific (as in mostly relevant articles but probably omitting a few), or Optimized (as in the combination of terms that optimizes the trade-off between sensitivity and specificity). A detailed explanation of the strategies behind these limits can be found at http://hiru.mcmaster.ca/hiru/HIRU_Hedges_MEDLINE_Strategies.aspx.

The Clinical Queries are based on the work of R. Brian Haynes MD, PhD et al. of the Health Information Research Unit (HIRU) at McMaster University, are intended for clinicians.

Sentence syntax for the limits is as follows.

  • limit 1 to "Therapy (sensitivity)"
  • limit 1 to "Therapy (specificity)"
  • limit 1 to "Therapy (optimized)"

A complete list of queries is available from within the Ovid interface.

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Tools

The following Search Tools are available for this database. For specific information on using these tools, refer to the Ovid Online Help linked below.

  • Tree

    Note: Because MEDLINE includes Check Tags as limits, if you search for any of these terms in Advanced Search as an unqualified search, instead of showing the "map to subject heading" display, the search for that check tag will be excuted automatically. However on Ovid the only Check Tags that still exhibit this behaviour are "Male" and "Female". On customer request all other checktags will map to the MeSH Tree just like any other search term.

  • Permuted Index
  • Scope Notes
  • Explode
  • Subheadings

Note about Pharmacological Actions and MeSH tree for Ovid MEDLINE:

Unlike PubMed, Ovid MEDLINE only has 1 hierarchical tree. Therefore the Pharmacological Actions are included in the Ovid MEDLINE tree display as "[Drug Terms (Non MeSH)]". Secondly the "explode function" on Ovid automatically includes Pharmacological Actions when applicable.

Example: exp air pollutants/

  • Includes all MeSH terms for Air Pollutants: Air Pollutants/, "Air Pollutants, Occupational"/, "Air Pollutants, Radioactive"/, "Greenhouse Gases"/
  • Includes all Pharmacologic Actions MeSH terms: Gasoline/, Hydrogen Sulfide/, Particulate Matter/, Radon/, Sulfur Dioxide/, Vehicle Emissions
  • Does not include the Supplementary Concept terms for Air Pollutants: 1,6-hexamethylene diisocyanate, 2-nitrofluoranthene, 2-nitrofluorene, bisphenol A, methyl tert-butyl ether, silicon nitride.
Supplementary Concept terms for Chemicals and Drugs are indexed in Ovid MEDLINE under the Registry Number/Name of Substance (RN) field.

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Database Coverage

Ovid MEDLINE provides content equivalent to PubMed. It is updated daily with a 1-day delay on Tuesday-Friday and 2 days on Monday compared to PubMed. Approximately 30,000 entries are listed in the daily updated PubMed journal list, which includes all MEDLINE® titles as well as other non-MEDLINE titles. The list covers the entire span of Ovid MEDLINE/PubMed, not just the currently indexed journals. You can find a daily updated list of the currently indexed journals in the NLM Catalog. Once a year, at the time of the annual reload, Ovid retrieves that journal list and makes it available as an Excel file: nlmcatalog_5-March-2024.xlsx

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Changing to this Database

To change a search session to an Ovid MEDLINE segment from another database or Ovid MEDLINE segment, use the change database icon on the Main Search Page or take advantage of the "..c" or "use" commands in Ovid Advanced Search, e.g.: ..c medall

How to utilize Ovid Command Line Syntax is also described in the Advanced Search Techniques section of the Online Help file

  Search Label:

Ovid MEDLINE® ALL 1946 to January 19, 2018:

MEDALL
        Ovid MEDLINE® Epub Ahead of Print Updated Daily: MEDP
        Ovid MEDLINE® 2015 to Weekly Update: MEDW
        Ovid MEDLINE® Updated Daily: MESX
        Ovid MEDLINE® Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE® Daily, Ovid MEDLINE and Versions® 1946 to Present with Daily & Weekly Update: PPEZV
        Ovid MEDLINE® In-Process & Other Non-Indexed Citations Updated Daily: PREW
  Command Syntax: ..c/medw
  Sentence Syntax: use medp

Click on this link to see other Advanced Search Techniques

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Sample Documents
Sample 1
Unique Identifier:
	33027187
Title:
	The impact of fungal allergic sensitization on asthma.
Title Comment:
	Comment in: Curr Opin Pulm Med. 2021 Jan;27(1):1-2; PMID: 33105236 [https://www.ncbi.nlm.nih.gov/pub...- opens in a new window]
Source:
	Current Opinion in Pulmonary Medicine. 27(1):3-8, 2021 Jan.
Abbreviated Source:
	Curr Opin Pulm Med. 27(1):3-8, 2021 Jan.
Version ID:
	1
Record Owner:
	From MEDLINE, a database of the U.S. National Library of Medicine.
Status:
	In-Data-Review
Authors:
	Kao CC; Hanania NA; Parulekar AD
Authors Full Name:
	Kao, Christina C; Hanania, Nicola A; Parulekar, Amit D.
Institution:
	Kao, Christina C. Section of Pulmonary, Critical Care, and Sleep, Department of Medicine, Baylor College of Medicine, Houston, Texas.
        Hanania, Nicola A. Section of Pulmonary, Critical Care, and Sleep, Department of Medicine, Baylor College of Medicine, Houston, Texas.
        Parulekar, Amit D. Division of Allergy, Pulmonary, and Critical Care, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Comments:
	Comment in (CIN)
NLM Journal Name:
	Current opinion in pulmonary medicine
Publishing Model:
	Journal available in: Print
        Citation processed from: Internet
NLM Journal Code:
	cn1, 9503765
ISO Journal Abbreviation:
	Curr Opin Pulm Med
Journal Subset:
	Index Medicus
Country of Publication:
	United States
Abstracts: 
        PURPOSE OF REVIEW: Fungal sensitization may contribute to the development of asthma as well as asthma severity. The purpose of this review is to summarize existing knowledge 
        about the pathophysiology, diagnosis, and management of fungal sensitization in asthma and highlight unmet needs and target areas for future investigation.

        RECENT FINDINGS: Fungal sensitization may occur by a normal or aberrant immune response. Allergic sensitization to fungi is mediated by the adaptive immune response driven by 
        TH2 cells and the innate immune response driven by the innate lymphoid cells group 2. Diagnosis of fungal sensitization can be made by either skin prick testing or measurement 
        of fungal-specific serum IgE. Fungal sensitization in asthma has been associated with worse disease severity, including reduced lung function, increased risk of hospitalizations, 
        and life-threatening asthma. A spectrum of disease related to fungal sensitization has been described in asthma including allergic bronchopulmonary mycosis and severe asthma with fungal    
        sensitization (SAFS). The role of antifungals and targeted biologic therapy in asthma with fungal sensitization need further investigation.

        SUMMARY: There is increasing awareness of the contribution of fungal sensitization to asthma severity. However, there are no therapies with proven efficacy. Randomized clinical trials
        are needed to further investigate the role of biologics.
ISSN Electronic:
	1531-6971
ISSN Linking:
	1070-5287
Digital Object Identifier:
	https://dx.doi.org/10.1097/MCP.0...
Publication Type:
	Journal Article.
Article Identifier:
	10.1097/MCP.0000000000000740 [doi]
Publication Status:
	ppublish
Language:
	English
Date of Publication:
	2021 Jan
Entrez Date:
	2020/10/08 06:00
MeSH Date:
	2020/10/08 06:00
Create Date:
	2020/10/07 17:12
Year of Publication:
	2021
Revision Date:
	20201203
Update Date:
	20201215
Sample 2
Unique Identifier:
	33139226
Title:
	Myocardial infarction in times of COVID-19.
Title Comment:
	Comment on: Rev Esp Cardiol (Engl Ed). 2020 Dec;73(12):994-1002; PMID: 32917566 [https://www.ncbi.nlm.nih.gov/pub...- opens in a new window]
Source:
	Revista Espanola de Cardiologia. 73(12):975-977, 2020 12.
Abbreviated Source:
	Rev Esp Cardiol (Engl). 73(12):975-977, 2020 12.
Version ID:
	1
Record Owner:
	From MEDLINE, a database of the U.S. National Library of Medicine.
Status:
	In-Process
Authors:
	Ibanez B
Authors Full Name:
	Ibanez, Borja.
Institution:
	Ibanez, Borja. Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain; Instituto de Investigacion Sanitaria-Hospital Universitario Fundacion 
        Jimenez Diaz (IIS-FJD), Madrid, Spain; Centro de Investigacion Biomedica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain. Electronic address: [email protected].
Comments:
	Comment on (CON)
NLM Journal Name:
	Revista espanola de cardiologia (English ed.)
Publishing Model:
	Journal available in: Print-Electronic
        Citation processed from: Internet
NLM Journal Code:
	101587954
ISO Journal Abbreviation:
	PRev Esp Cardiol (Engl Ed)
PMC Identifier:
        https://www.ncbi.nlm.nih.gov/pmc...
Journal Subset:
        Index Medicus
Country of Publication:
	Spain
ISSN Electronic:
	1885-5857
ISSN Linking:
	1885-5857
Publisher Item Identifier:
        S1885-5857(20)30461-8	    
Digital Object Identifier:
	https://dx.doi.org/10.1016/j.rec...
Publication Type
	Editorial. Comment.
Article Identifier
	S1885-5857(20)30461-8 [pii]
        10.1016/j.rec.2020.09.023 [doi]
        PMC7604101 [pmc]
Publication Status:
	ppublish
Publication History Status:	
        2020/09/21 [received]
        2020/09/22 [accepted]
Language:
	English Spanish
Electronic Date of Publication:	
        20201031
Date of Publication:
	2020 12
Entrez Date:
	2020/11/04 06:00
MeSH Date:
	2020/11/04 06:00
Create Date:
	2020/11/03 05:37
Year of Publication:
	2020
Entry Date:
	20200206
Revision Date:
	20201204
Update Date:
	20201215           
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