Medical Web
Introducing Online Resources and Terminology
Essay from Medicine and the Internet, 2nd edition, Chapter 27
by
Oxford University Press, 1997
(available through special discount offer)
? 1997 by Oxford University Press. Used with permission.
(Posted July 25, 1997 ? Issue 13; archived August 15, 1997)
For most people, "Internet" and "World Wide Web" are synonymous. Indeed,
it would not be untrue to say that if you cannot find something through the WWW, then that
something is not on the Internet. The WWW provides an interface to various forms of medical
information on the Internet in many ingenious ways. Broadly speaking, it does this through
different kinds of catalogues or directories, and search engines.
If you are looking for nonspecific resources or general information, a directory is a good place to start. For a more focused search, start with a search engine.
WWW-Based DirectoriesThere are several large multi-subject catalogues of Internet resources that cover medical topics, often dividing resources by clinical specialty or general health and medical subject headings. Most are also linked to powerful search engines (programs that look for information in response to a query). Search engines are covered under the next subheading; directories characteristically lend themselves to "casual browsing." The biggest advantage of manually created directories is the ability to include an annotation describing the resource - although not all directories choose to do this. When present, such annotations constitute a rudimentary form of peer review (see also standards and peer review, p. 116).
Other directories focus specifically on medicine and health care, again, usually indexing resources by medical specialty or broad subject. In general, these catalogues are more discriminating about which sites they index. Some medical catalogues aim to provide features such as annotations, fast search engines, more effective subject organization, or even training and documentation.
The most developed specialist index in the UK is OMNI (Organizing Medical Networked Information), funded by the Joint Information Systems Committee (JISC) and operated by a consortium including the British Medical Association Library, Medical Research Council, Wellcome Centre for Medical Science, and others. It is a searchable subject-based catalogue of UK and global medical education and research resources, providing a brief description of each resource. The NHSweb Directory is being developed for NHSnet (p.137) users, indexing resources on NHSweb the NHS intranet, (p.113) and the Internet.
Medical Matrix from Healthtel Corporation, with the support of the Internet Working Group of the American Medical Informatics Association, categorizes clinical Internet resources into specialties, journals, education resources, etc., that can be used free at the point of care. It can be browsed or searched at: Medical Matrix. Another popular and well-supported North American resource is MedWeb from the Emory University Health Sciences Center Library. CIC HealthWeb (Committee for Institutional Cooperation) is a cooperative project by the "Big Ten" U.S. university health-science libraries cataloguing medical specialty resources, and those in health and basic sciences.
Alternatives to Annotation
Another approach has been to attempt to map individual Web pages to the MeSH terms (p. 241)
used to index articles in MEDLINE. Although MeSH indexing can bedone manually,
Fowler et al. (1995) have described their experiments using
a "Web-MeSH Medibot," an automated tool for assigning MeSH terms to WWW
pages. Although further development is needed, such a Medibot could be used to create a
static index for organizing information, or as a search engine
operated via WWW browser. The Internet could eventually become a "second MEDLINE"
in its own right, complete with familiar options to refine and combine searches, etc.
CliniWeb, from the Oregon Health Sciences University, is a browsable index of clinically relevant information at the level of individual WWW pages, using the MeSH disease tree. Searches are mapped to the closest available MeSH term. In Europe, a similar service is provided by the Library and Medical Information Center at the Karolinska Institute in Stockholm.
Meta-DirectoriesThere are now so many catalogues that, in true Internet fashion, catalogues of catalogues have become necessary (known as meta-directories). An example is the Hardin Meta-Directory from the Hardin Library for the Health Sciences, University of Iowa.
WWW-Based Search EnginesSearch engines accessed via a Web page use fill-out forms (p. 207) to enter the search terms and criteria. Typically terms are entered into a text box, with modifications to search parameters made via pull-down menus, check boxes, etc. Clicking on the search button (or Excite equivalent) will return a hypertext page of links to files meeting your search criteria (known as "hits"). Rather than a simple list of file names or URLs, many search engines provide a small extract or other information about the file. Hits can be ranked in order of relevancy, calculated by the frequency with which the terms appear in a document, their proximity to one another, or their relative position in a Web page (e.g., in a header).
There are numerous individual search engines available. Each search engine operates
differently and consequently has different strengths and weaknesses depending on what you
are looking for. These tools may index WWW page titles, URLs, existing indexes, and often
the actual content of documents (see fig. 29). Some include newsgroup postings, files
in FTP archives, and gopher menu items - perhaps even by way of a multilingual search
form. Some search for individual keywords, others for phrases or the co-occurrence of
terms. Some allow searches with wildcards or Boolean operators. Some engines allow
limited searches for free, with further functionality available upon subscription.
Example search engines follow; all of these tools will tell you about themselves,
so these details have been omitted here:
Familiarize yourself with the capabilities of the index you choose; all have help pages explaining the various search options. This author has found AltaVista and Open Text to be particularly useful tools.
There are also search engines that confine themselves to medical information. Many of the specialist medical directories mentioned above are also searchable. WWW-based MEDLINE searches are considered in chapter 29. Another example is MediS from Docnet, a search facility for manually indexed abstracts and articles from major medical journals such as the British Medical Journal, Journal of the American Medical Association, and the New England Journal of Medicine.
In yet another approach, Health on the Net Foundation's Marvin search engine
employs a 12,000-word medical dictionary to search out documents
containing medical terms, using word weighting and word counts to determine relevance.
Users search the resultant smaller (yet hopefully more specific) database, rather than
the Internet at large. A database of reviewed sites is also available at
MedHunt (Health on the Net Foundation).
An easy way to access multiple search engines is to use a "meta-search engine," or a page that allows you to search several individual engines simultaneously. Although convenient, such searches don't offer the flexibility to alter search criteria as would an individual engine. Example meta-search engines are:
Other Ways to Locate Information
Remember that not all information on the Internet is located on the WWW. However, the WWW can provide a familiar interface to help you find relevant newsgroup postings (p. 177), gopher items (p. 194), frequently asked questions files (p. 178), people (p. 158), files in FTP archives (p. 182), and information indexed by WAIS (p. 196).
Intelligent Agents
In the near future so-called "intelligent agents" (information-seeking programs)
could be directed to roam the Internet scanning for items of intereston the user's
behalf. Their "artificial intelligence" lies in the ability to adapt
subsequent search patterns based on the results of earlier searches. With such an
agent looking for items matching the users individual information requirements with
a high degree of specificity, the clinician need concentrateonly on absorbing
information - not finding it.
Fowler, J., Kouramajian, V., Maram, S. et al. 1995. Automated MeSH indexing of the World Wide Web. In Proceedings of the Nineteenth Annual Symposium on Computer Applications in Medical Care, pp. 893-7. American Medical Informatics Association, Bethesda.
Endlinks
The Cybert@s Index Page - home page of Bruce C. McKenzie, author of Searching the Medical Web, and editor of Medicine and the Internet: Introducing Online Resources and Terminology. Includes information on Bruce McKenzie's other writings, medical FAQ list, links to other medical Web sites, and to the home page of the Society for the Internet in Medicine.
BioMedNet's Evaluated MEDLINE - a unique MEDLINE service free to all BioMedNet members, Evaluated MEDLINE "rates" search results to point users to those of greatest significance. Evaluated MEDLINE also provides a Reference Manager and Endnote download facility.
MEDNET 97 announcement - announcement and call for papers for the 1997 World Congress on the Internet in Medicine, November 3-6, 1997, Brighton, United Kingdom. Topics to include telemedicine, medical education, hospital management and the Internet, research using the Internet, Internet security, and more.
The following are Web guides/search engines for health/medicine/science resources:
Yahoo's Health Indices - an alphabetical list of links on health/medicine topics, Reuters Health News, search engines, and more.
HotBot SciTech: Bio/Health - an alphabetical list of health/medical links and search engines, e.g. CancerNet, Essential Links to Medical Resources, Multilingual Glossary of Medical Terms, Reuters Health Information Services.
Webcrawler's Guide: Health - an alphabetical list of health topics, and a health feature of the week.
CNET's health resources index/search engine - search engine for various databases (e.g., AIDSTRIALS, CANCERLIT, HEALTHStar), links to HealthGate Free MEDLINE, Virtual Hospital, and more.
Excite's Health and Science Channel - an alphabetical list links to health and science topics and news, bulletin boards, and more.
Infoseek Health Topics - an alphabetical list of health topics/links, links to AMA Journals Report, and search engine.
LookSmart's Health & Fitness Professional Sites - links to medical libraries, journals, an alphabetical list of specialties, pharmacology, and more.