Both PubMed and Ovid versions of MEDLINE have stretched back in time. Older records which formerly made up a separate database called “OLDMEDLINE” are now included in regular MEDLINE searches. While MEDLINE used to contain citations only from the mid-1960s to present, searches now routinely cover materials back to 1953.
What is this older material and why would we want “old stuff?”
The National Library of Medicine (NLM) is engaged in a continuing project to make older biomedical, preclinical sciences and allied health sciences indexes available electronically. These materials are important as a researchers need to track down original research, methods and early findings. Remember the tragedy at Johns Hopkins when a research subject died because a key citation in the older literature was missed? NLM’s efforts to increase electronic access to older materials will help to address this type of problem.
The “new” older material adds approximately 1,525,000 citations to MEDLINE. These records do have some quirks. For example,
- none of them have abstracts;
- all are classified as just “journal article;”
- they use older subject headings, rather than the modern MeSH terminology; and
- those older subject headings are not included in the MH field.
So, topical searching of the older material requires keywords and text phrases. And one may not be able to apply some of the popular limits effectively (like “review articles”).
Even so, the inclusion of the OLDMEDLINE material is a wonderful step forward in convenience for researchers. You may want to attend one of AISR Education Services’ workshops on PubMed or Ovid MEDLINE as a refresher, to become familiar with this and other changes in the database.
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