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Number of Titles Currently Indexed for Index Medicus® and MEDLINE® on PubMed®

As of March 2014, 5,669 journals are currently indexed for MEDLINE. MEDLINE includes journals that are cited as Index Medicus as well as other non-Index Medicus journals. A breakdown is provided:

Number of Journals Subset of Journals Currently Indexed
5,096  journals indexed as Index Medicus
*573  additional, non-Index Medicus journals in the following areas:
  89 Dentistry (contribute to Citation Subset=D)
  18 AIDS/HIV (contribute to Citation Subset=X)
  15 Consumer Health (contribute to Citation Subset=K)
     183 Nursing (contribute to Citation Subset=N)
  105 Health care administration and delivery (contribute to Citation Subset=H)
  84 Health care technology indexed by NICHSR/NLM (contribute to Citation Subset=T)
  79 History of medicine core journals indexed fully by HMD/NLM (contribute to Citation Subset=Q or QIS)

*The number of non-Index Medicus journal titles dropped with the July and November 2013 updates due to a cleanup project to identify ceased journals or journals that NLM is no longer receiving data.

Note: The above count does not include current journals selectively indexed by the HMD (History of Medicine Division, NLM), and, in the past NASA (National Aeronautics and Space Administration), and the KIE (Kennedy Institute of Ethics) sources. NASA ceased its collaboration with NLM in October 2005. KIE ceased indexing for NLM in January 2006. NICHSR stands for National Information Center on Health Services Research and Health Care Technology, NLM.

It may be helpful to know:

  • The journal list groupings above were created for NLM in-house use, i.e., management of NLM indexing work flow.
  • A journal can belong to only one journal list.
  • These journal lists should not be confused with PubMed Subject Subsets. Subject Subsets may include citations from journals that are not part of the journal list for the same topic. For example, PubMed History of Medicine Subject Subset will not be limited to citations from the History of Medicine core journals
  • These journal lists should not be equated with PubMed Journal/Citation Subset data element (labeled as SB in the MEDLINE display format), although there is a connection between them. While a journal may belong to only one journal list, citations may be assigned multiple Citation Subset values. Every citation from a journal on a journal list will carry the Citation Subset value contributed by that journal list. Often when an Index Medicus journal fits into one of the special subject areas identified above, citations from that journal will have one Citation Subset value for Index Medicus and another Citation Subset value for the subject area. For example, British Dental Journal is an Index Medicus journal; citations from this journal have one Citation Subset value of IM for Index Medicus and a second Citation Subset value of D for Dentistry journal list. In addition, HMD and KIE, (and, in the past, NASA) may add their Citation Subset values to individual citations from any journal list title including Index Medicus journals. For example, this citation has three Citation Subset values of IM, D, and E for Ethics:

    Adewumi A, Hector MP, King JM.
    Children and informed consent: a study of children's perceptions and
    involvement in consent to dental treatment.
    Br Dent J. 2001 Sep 8;191(5):256-9.
    PMID: 11575761 [PubMed - indexed for MEDLINE]

  • Abridged Index Medicus (AIM) is a list created over 20 years ago of about 120 core clinical English language journals. It corresponds to the "Core clinical journals" subset in PubMed Limits.

For more information about journals see these resources: