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MEDLINE®/PubMed®
Baseline Repository |
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The records included in the MEDLINE/PubMed Baseline databases represent a static view of the data at the time each baseline database was created. To access the MeSH files under the MBR Files link, you must enter into an online Memorandum of Understanding for use of the MeSH Vocabulary data. To access the MBR Query Tool, you must be a recognized licensee of NLM Data. The License agreement requires those who use the MEDLINE/PubMed database to fill-out an Intended Use Worksheet once a year and to file a brief Usage Report (Note: research use licensees do not have to submit the Usage Report form) to summarize their use of the database. NLM leases MEDLINE/PubMed to U.S. individuals or organizations; to its formally recognized International MEDLARS Centers; and to non U.S. individuals or organizations for internal research projects with no commercial citation search service. We update the authorization information daily at 1800 Eastern Standard Time. We monitor and provide support for this site from 0800 to 1700 (Eastern Standard Time) Monday to Friday, excluding holidays. If you experience any problems while using the MBR web site, or would like additional information about leasing NLM data (other than the UMLS Metathesaurus), contact Jane Rosov, MEDLARS Management Section, National Library of Medicine, 8600 Rockville Pike, Bethesda, Maryland 20894, or e-mail NLMdatadistrib@nlm.nih.gov. Researchers have requested the ability to have available MEDLINE citations in the state they were at a given moment in time without the MeSH vocabulary updates and other revisions that occur during the year. The MEDLINE/PubMed Baseline Repository was setup to provide this capability. We have stored the end of year baseline of the MEDLINE/PubMed database for each year starting in 2002 along with a selection of the associated MeSH Vocabulary data files.
The baselines are normally generated towards the middle of November each year and contain all completed citations in MEDLINE as of that date. The baselines represent MEDLINE after the year-end processing has been completed. This means that the records have been revised with the upcoming year's new MeSH vocabulary terms. We currently have available the 2002 - 2008 MEDLINE/PubMed Baselines. The naming of the baselines represents this year-end processing. For example, the 2002 MEDLINE/PubMed Baseline contains all completed citations from the mid-1960's until the date the baseline was created in late November 2001 with the year-end processing assigning appropriate 2002 MeSH vocabulary terms, thus it is a baseline for the 2002 year. The baselines contain citations that are not MEDLINE as well. All of the baselines we have stored (2002 on) contain "Out-of-scope" citations which were renamed to "PubMed-not-MEDLINE" starting with the 2004 MEDLINE/PubMed Baseline. The PubMed-not-MEDLINE status refers to citations that reside in PubMed from journals included in MEDLINE and 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. Citations in the Out-of-scope or PubMed-not-MEDLINE status make up a very small percentage (0.51% or 75,271 records in the 2005 baseline) of the total number of citations contained in the baselines. Starting with the 2005 MEDLINE/PubMed Baseline, OLDMEDLINE citations are also included in the baselines. The OLDMEDLINE citations make up approximately 11% of the total number of baseline citations. The OLDMEDLINE citations are from international biomedical journals covering the fields of medicine, preclinical sciences, and allied health sciences. The citations were originally printed in hardcopy indexes published prior to 1966. For additional information, please refer to the following URL: http://www.nlm.nih.gov/databases/databases_oldmedline.html. In the 2005 baseline the subject indexing from the OLDMEDLINE citations were stored solely in the "Other Term" (or "OT") tagged fields and not the MeSH Terms (or MH) tagged fields. This means that searching the 2005 baseline from our MBR Query Tool via the MH field does not include any OLDMEDLINE citations. The only way to include OLDMEDLINE records in the 2005 baseline is to do a timeframe query without specifying any field specific search criteria. Beginning with the 2006 baseline, Other Terms are starting to be mapped to current MeSH Terms so that searching via the MH field may retrieve some OLDMEDLINE records, but, not necessarily the complete set of possibilities. Starting with the 2007 MEDLINE/PubMed Baseline, the citation status notation of OLDMEDLINE is going away. As the OLDMEDLINE terms are converted to MeSH Headings, the status will change to MEDLINE. You need to rely on the <CitationSubset> element in the XML files and the "SB" field in the MEDLINE ASCII files to determine whether a citation is OLDMEDLINE or not. For example,
We provide the following resources for each of the baselines for research purposes. Please note that background information on some of these resources is available from our MBR Reference Material page.
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| Last Modified: February 21, 2008 | ii-public | |||||||||||||||||||||||||||
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Lister Hill National Center for Biomedical Communications |
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U.S. National Library of Medicine |
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National Institutes of Health | |||||||||||||||||||||||
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Department of Health and Human Services | |||||||||||||||||||||||||||
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