MEDLINE®/PubMed® Resources Guide

MEDLINE® contains journal citations and abstracts for biomedical literature from around the world. PubMed® provides free access to MEDLINE and links to full text articles when possible.

The following resources provide detailed information about MEDLINE data and searching PubMed. If you cannot find the information you seek, please contact NLM Customer Service.

NEWS

PubMed New and Noteworthy:
List of changes to PubMed by date, with links to the Technical Bulletin.
NLM Technical Bulletin:
The NLM Technical Bulletin is your main source for detailed information about changes and updates to NLM resources, including MEDLINE and PubMed.
NLM-Announces:
NLM e-mail list for announcing important information and changes to NLM systems including PubMed.
PubMed-Alerts:
An announcements-only e-mail list that notifies subscribers of major system problems with PubMed, the MeSH Database and the NLM Catalog (Monday through Friday, 8:30am to 5:00pm ET).

OVERVIEWS

MEDLINE Fact Sheet:
A brief description of MEDLINE, your database of biomedical and life sciences journal citations. See also FAQ: Finding Medical Information in MEDLINE.
PubMed Fact Sheet:
A brief description of PubMed, part of the Entrez retrieval system and your free access to MEDLINE.
MEDLINE, PubMed, and PMC (PubMed Central): How are they different? (Fact Sheet):
A useful fact sheet to help you understand MEDLINE, PubMed, and PMC.
MeSH Fact Sheet:
To help you understand NLM's controlled vocabulary thesaurus. Helpful for searching NLM's databases. See also Medical Subject Headings (MeSH®)in MEDLINE®/PubMed®: A Tutorial and Branching Out: The MeSH Vocabulary (instructional video).
Indexing FAQ:
How indexing is done at NLM, and information on becoming an indexer.
Special Collaborative Arrangements:
An explanation of NLM's special collaborative arrangements for selecting publications.
What is the Cochrane Collaboration?:
An explanation of the collaboration created to improve clinical trials information in MEDLINE.
Reorganization of the NLM Databases (2002):
Where data from NLM's legacy databases went. See also FAQ: Retired Databases.

JOURNALS

MEDLINE Journal Selection (Fact Sheet):
How journals are selected for the MEDLINE database. See also the FAQ: Journal Selection for MEDLINE Indexing at NLM.
- Journals Recently Accepted by NLM for Inclusion in MEDLINE:
  Those titles recently accepted by the Literature Selection Technical Review Committee (LSTRC).
- Number of Titles Currently Indexed:
  The number of journal titles currently indexed for MEDLINE in PubMed.
- MEDLINE Selection Statistics
  Statistics on journal titles reviewed and selected by the Literature Selection Technical Review Committee (LSTRC) by date, country, and format.
List of MEDLINE Journals:
How can I find the list of journals indexed in MEDLINE?
- List of Journals Indexed for MEDLINE:
  A list of currently indexed titles, dynamically generated from the NLM Catalog.
- List of Serials Indexed for Online Users:
  A list of titles formerly and currently indexed in MEDLINE.
List of Journals in PubMed:
How can I find the list of journals included in PubMed?
- How do I know if my journal is indexed in MEDLINE/PubMed? (Journal Lists by FTP):
  PubMed and other Entrez journal lists available by file transfer protocol (ftp) in uncompressed, GNU zip, UNIX Compress, and PKZIP formats.
Journal and Citation Subsets:
The table of subset codes assigned to MEDLINE citations. See also Abridged Index Medicus (AIM or "Core Clinical") Journal Titles and FAQ: Finding a List of Abridged Index Medicus or Index Medicus Journal Titles.
Journal Subject Terms:
Subject Terms are assigned by NLM at the journal level to describe the journal's overall scope.
Use of Journal Title Abbreviations in NLM Databases:
An answer to the question, "Why does NLM still use journal title abbreviations rather than the full journal title in its citations?". See also Construction of National Library of Medicine Title Abbreviations.
MEDLINE Policy on Indexing Electronic Journals:
NLM policy for indexing, access, and preservation of articles from electronic journals.
- MEDLINE Journals Indexed from the Online Version:
  A list of journals indexed from the online version, with additional information on searching for online journals with LocatorPlus.
Ceased Abstracting and Indexing Publications Containing MEDLINE Citations:
Details about the MEDLINE and non-MEDLINE content of the Hospital Literature Index, the Hospital and Health Administration Index, the Index to Dental Literature, and the International Nursing Index.

DATA STRUCTURE & CONTENT

Detailed Field/Data Element Descriptions:
Descriptions of the fields in MEDLINE/PubMed records, with detailed historical information, when available.
MeSH Subheadings Table (from PubMed Help):
The MeSH subheadings and their abbreviations. See also the MeSH Qualifier (subheadings) Hierarchies.
PubMed Publication Types (from PubMed Help):
The publication types used in MEDLINE/PubMed. See also the Publication Characteristics (Publication Types) Scope Notes for definitions of publication types used in all NLM databases.
Languages in MEDLINE/PubMed:
A list of language codes and translations used in MEDLINE/PubMed.
PubMed Citation Status Subsets (from PubMed Help):
A list of status designations for PubMed records.
Journal and Citation Subsets:
The table of subset codes assigned to MEDLINE citations. See also Abridged Index Medicus (AIM or "Core Clinical") Journal Titles and FAQ: Finding a List of Abridged Index Medicus or Index Medicus Journal Titles.
Ceased Abstracting and Indexing Publications Containing MEDLINE Citations:
Details about the MEDLINE and non-MEDLINE content of the Hospital Literature Index, the Hospital and Health Administration Index, the Index to Dental Literature, and the International Nursing Index.
Grant Number Information Found in the GR Field:
The abbreviation, acronym and name for Institutes and Grants found in the ID field in MEDLINE.
Structured Abstracts:
A description of structured abstracts and how they are formatted for MEDLINE.
PubMed Character Conversions:
How special characters are translated in PubMed.
Code Designations for Greek Characters in the Gene Symbol Field:
How Greek characters are represented in MEDLINE in the Gene Symbol field (used only 1991-1995).
Special Collaborative Arrangements:
An explanation of NLM's special collaborative arrangements for selecting publications.
What is the Cochrane Collaboration?:
An explanation of the collaboration created to improve clinical trials information in MEDLINE.
NLM DTDs:
A DTD (Document Type Definition) defines the building blocks of an XML document. It defines the document structure with a list of allowable elements. These are the DTDs that define NLM's XML data. See also Leasing NLM Data
E-Utility DTDs:
The DTDs for the Entrez Databases, including MEDLINE and PubMed.
MEDLINE Databank Sources:
Names that appear in the DataBankName element in the XML version of the citation and the Secondary Source ID [SI] element in the PubMed MEDLINE display.

DATA POLICIES

Detailed Field/Data Element Descriptions:
Descriptions of the fields in PubMed/MEDLINE records, with detailed historical information, when available. (Note: This document contains policy information for selected data elements.)
Annual MEDLINE/PubMed Year-End Processing Activities:
A description of the annual maintenance, known as year-end processing, done primarily to update MEDLINE citations to the forthcoming year’s version of MeSH.
Article Versions and MEDLINE/PubMed Citations (FAQ)
What is and is not a versioned citation from the National Library of Medicine point of view.
Authorship in MEDLINE:
Information on how authorship is reflected in MEDLINE.
Clinical Trial Registry Numbers in MEDLINE/PubMed Records:
Clinical trials information in MEDLINE/PubMed records.
Conflict of Interest Disclosure and Journal Supplements in MEDLINE:
The conditions under which supplements are cited and indexed for MEDLINE.
Construction of National Library of Medicine Title Abbreviations (Fact Sheet):
How journal title abbreviations are constructed.
Copyright Information & Downloading National Library of Medicine Data:
Guidance for redistribution of MEDLINE/PubMed and other NLM data.
Errata, Retraction, Partial Retraction, Corrected and Republished Articles, Duplicate Publication, Comment, Update, Patient Summary and Republished (Reprinted) Article Policy for MEDLINE (Fact Sheet):
NLM policies on these publication events.
MEDLINE/PubMed Journal Article Citation Format:
Background on the citation style used in MEDLINE/PubMed. See also Sample References (International Committee of Medical Journal Editors Recommendations for the Conduct, Reporting, Editing and Publication of Scholarly Work in Medical Journals)
Multiple Language Translations of Online Journals and Indexing English Editions of Journals:
MEDLINE/PubMed includes a language field for identifying the languages in which an article is published.
Research Reporting Guidelines and Initiatives: By Organization:
A chart of the major biomedical research reporting guidelines that provide advice for reporting research methods and findings.
Structured Abstracts:
A description of structured abstracts and how they are formatted for MEDLINE.

SEARCHING PUBMED

(See also Help and Training Resources)

PubMed Search Field Descriptions and Tags (from PubMed Help):
A table of all searchable fields in PubMed.
MeSH Qualifier (Subheading) Hierarchies:
Subheadings arranged in their logical hierarchical groupings, or families. Searching a broader subheading in PubMed will automatically search more specific subheadings.
PubMed Subset Strategies:
The search strategies for each PubMed subject subset.
Clinical Queries Filter Table:
Search filters for each clinical and medical genetics category for the PubMed Clinical Queries.
Special Queries:
A directory of topic-specific PubMed queries.
Journal and Citation Subsets:
The table of journal and citation subset codes assigned to MEDLINE citations . See also Abridged Index Medicus (AIM or "Core Clinical") Journal Titles and FAQ: Finding a List of Abridged Index Medicus or Index Medicus Journal Titles.
Journal Subject Terms:
Subject Terms are assigned by NLM at the journal level to describe the journal's overall scope.
Citations by Funding Support:
An explanation and statistics of research funding support information on MEDLINE citations.
Computation of Similar Articles:
A white paper that explains the function of the Similar Articles feature.
What are the date ranges for past MeSH Indexing years?
Information about the date ranges for indexing with MeSH. Includes tips for searching.

TOOLS & UTILITIES

The Insider's Guide to Accessing NLM Data
The Insider's Guide is a series of educational resources to help users explore more powerful and flexible ways of accessing NLM data, with a focus on accessing PubMed data via the E-utilities API.
E-Utilities Quick Start:
The Entrez Programming Utilities (or E-Utilities) provide a method for accessing Entrez (including PubMed) data outside of the regular Web query interface.
LinkOut:
The service that links PubMed records to full text providers and other external resources related to the citation.
Leasing NLM Data:
Information on leasing MEDLINE/PubMed and other NLM data.
PMCID/PMID/NIHMSID Converter:
Convert PubMed IDs to PubMedCentral IDs or NIH Manuscript System IDs. Convert PubMedCentral IDs to PubMed IDs.

MEDLINE® STATISTICS

Key MEDLINE Indicators:
Citations indexed, number of searches, journal titles, citations keyboarded, OCRed and retrieved via XML; retractions, errata and comments.
Number of Titles Currently Indexed:
The number of journal titles currently indexed for MEDLINE in PubMed.
MEDLINE Selection Statistics
Statistics on journal titles reviewed and selected by the Literature Selection Technical Review Committee (LSTRC) by date, country, and format.
Indexing Statistics:
- Detailed (Yearly)
- Summary (5 Year Increments)
Number of journals and citations indexed for Index Medicus and MEDLINE, by year and by five-year period.
Citation Counts by Year of Publication:
Total number, number published in the U.S., and percent published in the US for each year of publication.
Authors per Citation:
Number of personal authors and collective authors per citation, and trends over time.
MEDLINE Data Entry by Fiscal Year:
Total citations entered by keyboarding, OCRed and received electronically in XML.
Citations Added to MEDLINE by Fiscal Year:
Total of indexed citations by fiscal year.
Number of Citations to English Language Articles; Number of Citations Containing Abstracts:
By date ranges, the number and percent of citations to English language and non-English language articles, and number and percent with abstracts.
Citations by Funding Support:
An explanation and statistics of research funding support information on MEDLINE citations.
Statistical Reports on MEDLINE/PubMed Baseline Data:
Total citations containing each data element; total occurrences of each element; minimum/average/maximum occurrences of each element in a record; minimum/average/maximum length of a single element occurrence; average record size; and other statistical data describing the content and size of the elements. Various data from 2002-.
PubMed Searches:
The average number of PubMed searches per average day in the last year.

HELP & TRAINING RESOURCES

PubMed Online Training Resources:
The PubMed Tutorial, Quick Tours and more. See also NLM's Distance Education Resources.
Classroom Training (National Network of Libraries of Medicine Training Office):
Free PubMed courses available for health sciences librarians and information specialists in the United States.
PubMed Frequently Asked Questions:
Frequently asked questions about MEDLINE and PubMed. See also the MEDLINE/PubMed FAQ.
PubMed Glossary:
A glossary of terms used with MEDLINE and PubMed, from the PubMed Tutorial.
PubMed Help:
Searchable Help document for PubMed, available on the NCBI Bookshelf.

U.S. National Library of Medicine