Index Medicus

Index Medicus (IM) was a comprehensive bibliographic index of scientific journal articles focusing on medical science fields, published from 1879 to 2004. It was initiated by John Shaw Billings, head of the Library of the Surgeon General's Office, United States Army. This library later evolved into the United States National Library of Medicine (NLM). In the 1960s, the NLM began computerizing the indexing work by creating MEDLARS, a bibliographic database, which became MEDLINE. Index Medicus thus became the print presentation of the MEDLINE database's content, which users accessed usually by visiting a library which subscribed to Index Medicus (for example, a university scientist at the university library). It continued in this role through the 1980s and 1990s, while various electronic presentations of MEDLINE's content also evolved, first with proprietary online services (accessed mostly at libraries) and later with CD-ROMs, then with Entrez and PubMed. As users gradually migrated from print to online use, Index Medicus print subscriptions dwindled. During the 1990s, the dissemination of home internet connections, the launch of the Web and web browsers, and the launch of PubMed greatly accelerated the shift of online access to MEDLINE from something one did at the library to something one did anywhere. This dissemination, along with the superior usability of search compared with use of a print index in serving the user's purpose (which is to distill relevant subsets of information from a vast superset), caused the use of MEDLINE's print output, Index Medicus, to drop precipitously. In 2004, print publication ceased. In one sense, Index Medicus and Abridged Index Medicus still exist conceptually as content curation services that curate MEDLINE content into search subsets or database views (in other words, subsets of MEDLINE records from some journals but not others). This filters search results with a view toward excluding poor-quality articles (such as by excluding junk journals), which is often helpful depending on the needs of the user.