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United States National Library of Medicine National Institutes of Health

Fact Sheet
Bibliographic Services Division (BSD)

The Bibliographic Services Division, a part of Library Operations, provides access to biomedical literature. It does this primarily through MEDLINE®, the online database containing references, citations and abstracts, to articles in biomedical and life sciences journals. MEDLINE derives its name from an older acronym phrase, MEDLARS® Online, which stands for Medical Literature Analysis and Retrieval System Online. Statistical data are available at:

The Division has two sections: Index Section and MEDLARS Management Section. In addition, the staff of the Office of the Chief, BSD, is responsible for interactions with publishers and editors of biomedical journals and administration of NLM's Literature Selection Technical Review Committee (LSTRC) in its review of journals for inclusion in MEDLINE. The Division works with publishers of journals recommended by LSTRC to receive acceptable electronic citation and abstract data for inclusion in MEDLINE.

Index Section

The Index Section, which produces MEDLINE data, is the largest component of BSD. The Section creates bibliographic citations for each article published in journals covered by MEDLINE, and performs subject analysis by which concepts that are discussed in each indexable article are assigned one or more descriptors from the Medical Subject Headings (MeSH®) controlled vocabulary. More than 16 million articles from approximately 5,200 biomedical journals have been indexed for MEDLINE since its inception in 1966; more than 670,000 articles were indexed in 2007. The Index Section also performs gene indexing by creating annotated links between MEDLINE citations and records for genes and proteins in the Entrez Gene database (see NLM Technical Bulletin article, Gene Indexing and Entrez Gene).

Indexers are biomedical subject specialists with degrees in science, and many are also experts in one or more foreign languages because the Section analyzes journals written in approximately 37 languages. Foreign language specialists from the Section assist the Literature Selection Technical Review Committee (LSTRC) in reviewing non-English journals for possible inclusion in MEDLINE.

Most subject indexing is performed by contractors, some is produced in-house, and some by International MEDLARS Centers located in England, Sweden, Brazil and China. Indexers examine the full text of articles, whether in print or electronic format; they do not rely on abstracts to convey the contents of the full article. See also Frequently Asked Questions about Indexing.

Members of the Index Section train new indexers and review the work produced outside of NLM for accuracy and consistency. In addition, the Section's chemical specialists add about 8,500 new supplementary concepts (mostly chemical) to the MeSH headings each year, and indexers supply suggestions for new MeSH terms because they continually encounter new concepts in the literature. Members of the Index Section assist in the definition, treeing, and annotation of new MeSH concepts.

Article citations may be supplied electronically by publishers, subject to review for completeness and accuracy by bibliographic specialists working under contract; or produced by a combination of scanning and optical character recognition-assisted technology (also performed by contractors). Completed citations may be linked by the Index Section staff to related citations. See the NLM fact sheet Errata, Retraction, Partial Retraction, Corrected and Republished Articles, Duplicate Publication, Comment, Update, Patient Summary and Republished (Reprinted) Article Policy for MEDLINE. The Index Section also corrects MEDLINE errors detected by users.

MEDLARS Management Section (MMS)

MMS is responsible for facilitating and improving access to bibliographic data and publications. Their primary focus is database development, management, testing and quality assurance to foster expanded access of health information to health professionals and the general public. MMS staff collaborates with the National Center for Biomedical Information (NCBI), Lister Hill Center (LHC), and Office of Computer and Communications Systems (OCCS) staff on development and refinement of search screens, new features, and testing of new versions of PubMed®, the NLM Gateway, and UMLS-related system tools. There is ongoing testing for data quality and investigation of reports from the public of questionable data. Most MMS staff are librarians or technical information specialists.

MMS also develops national training programs, online training and user documentation for PubMed, the NLM Gateway, UMLS® (Unified Medical Language System®), and; manages NLM's data licensing and distribution programs for NLM and UMLS data; incorporates user feedback into product development; performs software and system testing for UMLS, MEDLINE, and PubMed systems; and answers specialized customer inquiries. MMS staff assists with the LinkOut program and the NIH Manuscript Submission process. MMS leads the conversion of older citations from pre-1966 printed indexes and the mapping of the old keywords assigned to those citations to current MeSH, both of which increase the amount of data available to users.

A complete list of NLM Fact Sheets is available at:
(alphabetical list)
(subject list):

Or write to:

Office of Communications and Public Liaison
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Bethesda, Maryland 20894

Phone: (301) 496-6308
Fax: (301) 496-4450

Last reviewed: 12 May 2008
Last updated: 12 May 2008
First published: 21 March 2005
Metadata| Permanence level: Permanent: Stable Content
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