Online Medical Databases

Bryan Bergeron, MD

In This Article

Online Databases

The archetypical online medical database portal is Entrez, established and maintained by the National Center for Biotechnology Information or NCBI (Figure 3). Entrez is a good example of a useful portal to online medical database because the data are referenced, the site is free of commercial influence, it's run by a government agency with academic oversight, it's easy to use, it's updated daily, and, fortunately, it's free.

NCBI's Entrez portal home page. Entrez is easily the most often used online medical database portal. PubMed, the biomedical literature database is one of the clinically useful databases within Entrez.

Although Entrez serves as a portal to the bioinformatics and molecular biology research community, it also provides access to 6 very useful clinical databases, PubMed, OMIM, Books, Journals, PMC, and NCBI Web site, as listed in the Table below. In addition to more research-oriented databases, Entrez provides access to several key clinical databases.

Most readers are probably familiar with PubMed, which can be used to search for a publication by author, journal, topic, or date. However, less well known but worth visiting is OMIM, the Online Mendelian Inheritance in Man database. The OMIM database is a catalog of genetic disorders authored by physicians and scientists at Johns Hopkins University, Baltimore, Maryland, and elsewhere, and developed by NCBI. The database contains heavily referenced review articles that are links to the biomedical literature and additional related resources on the Web.

Two relatively new additions to Entrez are PMC (PubMed Central) and NCBI Web site. PMC is the US National Library of Medicine's digital archive of life sciences journal literature. Access to the full text of articles in PMC is free, except where a journal requires a subscription for access to recent articles. Most of the articles can be downloaded as either text files or as formatted PDF documents. The latter requires the installation of a free Adobe Acrobat reader. NCBI Web site is a database of the home pages available within Entrez. For example, a search for "diabetes" returns 41 home pages within Entrez that contain information relevant to diabetes.

Entrez differs from most other online database systems in the degree to which the databases within the system are linked. That is, instead of constantly re-entering a search term every time a different database is searched, most of the databases within Entrez "remember" the current search thread and continue with it throughout the search. Linked databases save time, effort, and reduce errors due to miskeying search terms on subsequent searches. Entrez is also unique among most online medical databases in that it is configured to facilitate knowledge management. Researchers with new gene sequence data associated with a publication, for example, can upload the data to the appropriate national databases within Entrez. Once in the system, the data are validated and included in the appropriate database.

In addition to online databases sponsored by the government and academia, such as Entrez, there are hundreds, if not thousands, of databases established by pharmaceutical companies, physician boards and other specialty organizations, print publications, and medical students and residents with varied levels of expertise. These sites vary considerably in quality of content, amount of peer review, and the bias of the firm or individual hosting the service. A few of the many notable clinical sites worth visiting, in addition to Medscape from WebMD, are:

  • MedicineNet -- contains a reasonable medical dictionary and medication index function. You'll have to contend with numerous advertisements, however.

  • EMedicine -- provides thousands of peer-reviewed articles on a spectrum of medial topics in 62 medical specialties. Academic requirements for authors and editors are listed on the home page.

  • The British Medical Journal (BMJ) -- the site is free and up-to-date. Most articles are available as text files or formatted as PDFs.

  • The Journal of the American Medical Association (JAMA) -- free, up-to-date, and articles are available as text files or PDFs.

These sites range from conservative, advertisement-free services (eg, BMJ) to heavily advertised sites (eg, MedicineNet). The URLs for these and other databases are listed near the end of this document.


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