Medical Directories and Subject Guides, compiled by professional organizations, educational institutions, commercial firms, and individuals, are useful jumping off spots. Some major medical guides follow (Excessive "linking to links" can be frustrating):
Search Engines are hugh (claiming up to 3 billion pages), allow you to enter specific words or phrases, then look for web pages that contain those search strings in titles or content. Each search engine has different ways of entering search strings, indexes different (but overlapping) selections of web sites or other Internet services, and looks at different sections of pages for indexing. The best search engines allow you to refine results.
Selected Search Engines:
From UC Berkeley The Best Search Engines
, "For most searches, Google is the best place to start. It has one of the largest, if not the largest, database of Web pages, including many other types of Web documents (e.g., PDFs, Word or Excel documents, PowerPoints). However, Google alone is not sufficient
. Less than half the searchable Web is fully indexed in Google. Overlap studies show that about half of the pages in any search engine database exist only in that database. For a second opinion, we recommend Teoma
Meta-search Engines automatically submit your keyword search to several search engines, and display sets of documents from each one searched. They are useful if you are looking for a unique term or phrase (enclose phrases in quotes " "); or if you simply want to test run keywords in several search engines.
Meta-Search Engines: When to use and not use them? - for information on search engines covered, search features, and results display. Caveat: Meta-search engines only spend a short time in each database and often retrieve only 10% of any of the results in any of the databases queried. Meta-searchers simply pass your search terms along, and if your search contains more than one or two words or very complex logic, most of that will be lost. None of them queries Northern Light or Fast Search, two of the best and biggest search engines currently in existence. They are, however, a good jumping off point.
Review Sites provide evaluation and reviews of Internet sites. They are classified and searchable by subject.
Invisible Web Search Engines search in any of thousands of specialized searchable databases, and find data not easily or entirely searchable from general search tools.
a Yahoo-like directory. It is a high quality, human edited and indexed, collection of highly targeted databases. Helpful categories include "Health" and "Life Sciences" under Sciences.
see categories Medicine & Pharmaceuticals/Drugs
IncyWincy The Invisible Web Search Engine
A Collection of (mainly) Special Search Engines excellent list from the University of Leiden. See subjects Biology/Biosciences, Genetics, Medicine/health, Psychology.The
Invisible Web: Database contents rarely found in search engines for information on search features, size, etc.
2. Structuring a search:
Define the individual concepts you are looking for. What words or phrases are likely to occur? Are there unique terms that will focus your search?
Enclose phrases in double quotes to link the words together, i.e., "dietary supplements," "american osteopathic association"
Use Boolean terms to define the relationships between the concepts.
"AND" or the equivilent "+" requires ALL words or phrases - asthma AND "Vitamin E"
"OR" allows ANY of the words or phrases - vitamins or minerals or herbals or "dietary supplements"
"AND NOT" or the equivilent "-" excludes words or phrases - herbs AND NOT culinary
Use truncation to pick up variant endings - neuro* to retrieve neurology or neurological or neuroscience.
3. Evaluating Sites
Judge the source. An academic institution, leading professional organizations, government agency, respected publishers has more credibility than a commercial outfit (AllHealthStore.com) or an individual Joe'sMedicalCures).
Is a name or e-mail contact provided? Who authored the page and claims responsibility for it?
If the sponsoring body is not evident from the document itself, the URL will usually give clues to its source. For example: http://www.nlm.gov/
indicates a WWW document put up by a government organization with nlm as part of its title.
Is there a clear bias - i.e., is the information promotional, does the site sell a product? note: the bias in favor of "edu," "gov," and "org" over "com" is often valid.
How current is the site? What is the date of the last update?
Beware of commercial search engines' "the best of . . ." Frequently the emphasis is on graphic, "cool" or "really neat" aspects of a site. Consult review sites.
Review the Health On the Net Foundation Code of Conduct (HONcode).
4. Tutorial : Finding Information on the Internet - a Teaching Library Internet Workshop from the University of California, Berkeley.
1. Question the validity of the information - anyone can put anything on the Web.
2. Check currency of the site.
3. Expect sites to move and change urls.
4. Analyze your topic; identify every relevant concept.
5. Structure your question; how do the different concepts fit together?
6. Exploit the unique capabilities of the different search engines to refine your search and target retrieval.
7. Vary your search strategy - use review sites and directories along with and search engines.
6. Contribute to PCOM web site development.
Identify and evaluate web resources for professionals and patients.
Complete the Web Site Review Form.
Share your knowledge of unique and valuable sites with others through the PCOM Digital Library.