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The National Library of Medicine (NLM) began publishing Index Medicus, a comprehensive, print bibliographic index of medical articles, in 1879, at which point it was most often found in research and medical libraries. The production of Index Medicus evolved over time and a computerized version called Medical Literature Analysis and Retrieval System (MEDLARS) began in 1963. At that time, NLM patrons could also submit requests to retrieve citations via MEDLARS instead of using the print indices.

In the late 1960’s, the NLM also began the distribution of Index Medicus citation data through the production of computer data tapes. These tapes were distributed to libraries and organizations which provided localized computer access to the citation data.

In 1971, NLM began providing access to Index Medicus content via the MEDLARS onLINE (MEDLINE) system, which utilized specialized telecommunications systems. This system provided access to medical journal citations, published from 1966 and forward, that were included in Index Medicus. Accessing MEDLINE required training in the command line syntax used to search the database. 

During the mid-1980’s, NLM developed a software program called Grateful MED that was intended to expand and ease access to the NLM databases, including MEDLINE. Grateful Med was a more user-friendly front-end to MEDLARS and was in use between 1986 and 2001.

In 1997, PubMed was launched, allowing access to the MEDLINE data through the internet. The previous online version of MEDLINE accessed through MEDLARS was discontinued during this time period. The print Index Medicus continued to be published until 2004.

MEDLINE date coverage has since been expanded to include journal article citations from two additional print indices: Cumulated Index Medicus (CIM) and the Current List of Medical Literature (CLML). Citations from these indices start from 1946.

A timeline of MEDLINE.

Last Reviewed: January 19, 2024