United States National Library of Medicine National Institutes of Health

FAQ: MEDLINE Citations Prior to 1949

Question: Why am I retrieving MEDLINE citations with publication dates prior to 1949?

Answer:

MEDLINE contains citations indexed 1949 to the present. Approximately 5,500 citations are for articles that were published earlier, but appeared in indexes published in 1949 or later. For more information on:

OLDMEDLINE Data
http://www.nlm.nih.gov/databases/databases_oldmedline.html
MEDLINE Fact Sheet
http://www.nlm.nih.gov/pubs/factsheets/medline.html

Return to the list of FAQs
http://www.nlm.nih.gov/services/faq.html

Last reviewed: 05 August 2009
Last updated: 03 July 2008
First published: 23 April 2003
Metadata| Permanence level: Permanence Not Guaranteed