In 1997, the National Library of Medicine (NLM) helped initiate a new era in American medicine when it made MEDLINE, its comprehensive online bibliography of published medical information, accessible to the public through the World Wide Web. That event may prove to be a symbolic watershed of 20th century American medicine. It will impact every aspect of medicine, from the manner in which physicians are educated to the way they run their daily practices. In order to understand why this is so, we need to examine how and to whom medical information was previously disseminated in this country.
The Roots of MEDLINE
The collection and distribution of medical information in America has always been intimately tied to the NLM. The NLM began with a few dozen books and journals in the library of Joseph Lovell, the first Surgeon General of the United States Army (Wyndham, 1985). Thirty years after his death, at the end of the Civil War, the library had only grown to 2,000 volumes. That changed in 1867 when John Shaw Billings was appointed librarian and began to aggressively purchase books and journals from all over the world. As the library grew, however, it became more and more difficult to find specific information, especially in the bound journals. To solve this problem, Billings personally began the enormous task of creating a subject index for the library's journal collection. Index Medicus, the monthly bibliography of the world's medical literature, was an outgrowth of his early card catalog. It was first published in 1879 and soon became the library's best known service.
By the 1960s, the process of collecting, cross-referencing and printing thousands of new Index Medicus citations each month had become such a chore that a computer database system, MEDLARS (Medical Literature Analysis and Retrieval System), was developed to speed the process. MEDLARS was initially used to conduct literature searches within the NLM and to prepare the printed version of Index Medicus. In 1972 the NLM expanded access to the system through MEDLINE (MEDlars onLINE), an online computer service that gave medical libraries around the country the ability to search the Index Medicus database. Unfortunately, the early MEDLINE searches were so complicated that they could only be conducted by trained librarians.
As the number of requests for MEDLINE searches increased, the cost of providing the service became prohibitive. This problem was solved in the 1980s by the development of simpler computer programs like Grateful Med that gave people without extensive computer training the means to perform their own MEDLINE searches. Most medical libraries offered free MEDLINE access to their health care professionals using this software. Physicians who did not live near a medical library had to conduct their searches through private information companies that charged an hourly fee for the service.
In the early 1990s the pharmaceutical industry remedied this problem by offering free MEDLINE service to every physician who had access to a personal computer. The NLM's recent decision to provide free access to MEDLINE on the World Wide Web is a significant step beyond that. It represents a policy decision by the government that medical information should be freely available, not only to physicians, but to every citizen.
How to Find MEDLINE
You can gain access to MEDLINE through the National Library of Medicine's Web site at <http://www.nlm.nih.gov>. Once you arrive at the NLM home page, click on the button that says "Free MEDLINE." The next page that appears will provide entry to the NLM's two search systems, Internet Grateful Med and PubMed. Both systems allow you to search MEDLINE and several other medical-biology databases. Internet Grateful Med is an adaptation of the online search software that was used for many years before the development of the Internet. It's easy to use and adequate for most literature searches.
PubMed is based on an entirely new concept. It is the central component in what will eventually become a comprehensive Internet biomedical information network. PubMed was developed by the National Center for Biotechnology Information, at the NLM, in conjunction with several publishers who provide the complete text of their journals, including tables and illustrations, on the Web.
PubMed links MEDLINE citations directly to the articles in these full-text journals. This means that when you find a specific citation in the MEDLINE database you can go directly to the article at the publisher's Web site. Furthermore, the references at the end of these articles are also linked to MEDLINE and to other full-text journals. If a reference cites a journal that is on the Web, a click on the reference will take you directly to the cited paper.
Other Journals on the Web
Currently, almost 100 clinical and research journals offer full-text versions on the Web. Most charge a subscription fee. Some offer free trial periods. You can find a list of all these journals at <http://www.ncbi.nlm.nih.gov/PubMed/fulltext.html>.
Most of the journals allow you to print copies of articles. The easiest way to do this is to print the article directly from your browser. This will give you all the text, tables and illustrations, but the printed copy will not look the same as the bound journal version. For that, you must download a copy of the article in PDF file format. PDF files are written in a special publishing language that allows you to reproduce the article exactly as it looks on the printed journal page. In order to view or print a PDF file you must have a copy of Adobe Acrobat Reader software installed on your computer. This program can be downloaded free from the Adobe web site at <http://www.adobe.com>.
NLM (1997), Vice President Launches Free Access to World's Largest Source of Published Medical Information on World Wide Web. National Library of Medicine. June 26. (http://www.nlm.nih.gov/news/press_releases/free_medline.html).
Osler W (1947), Aequanimitas, 3rd ed. Philadelphia: The Blakiston Company.
Starr P (1982), The Social Transformation of American Medicine. New York: Basic Books.
Wyndham MD (1985), A History of The National Library of Medicine. National Institutes of Health NIH Publication No. 85-1904.