Bioinformatics: searching the Net

During the past 30 years, there has been an explosion in the volume of published medical information. As this volume has increased, so has the need for efficient methods for searching the data. MEDLINE, the primary medical database, is currently limited to abstracts of the medical literature. MEDLINE searches use AND/OR/NOT logical searching for keywords that have been assigned to each article and for textwords included in article abstracts. Recently, the complete text of some scientific journals, including figures and tables, has become accessible electronically. Keyword and textword searches can provide an overwhelming number of results. Search engines that use phrase searching, or searches that limit the number of words between two finds, improve the precision of search engines. The development of the Internet as a vehicle for worldwide communication, and the emergence of the World Wide Web (WWW) as a common vehicle for communication have made instantaneous access to much of the entire body of medical information an exciting possibility. There is more than one way to search the WWW for information. At the present time, two broad strategies have emerged for cataloging the WWW: directories and search engines. These allow more efficient searching of the WWW. Directories catalog WWW information by creating categories and subcategories of information and then publishing pointers to information within the category listings. Directories are analogous to yellow pages of the phone book. Search engines make no attempt to categorize information. They automatically scour the WWW looking for words and then automatically create an index of those words. When a specific search engine is used, its index is searched for a particular word. Usually, search engines are nonspecific and produce voluminous results. Use of AND/OR/NOT and "near" and "adjacent" search refinements greatly improve the results of a search. Search engines that limit their scope to specific sites, and metasearch sites that use multiple search engines optimized for specific types of searches have recently emerged. The distinctions between search engines and directory searches have blurred. Eventually, conceptual searching in which the computer searches for related ideas, without having to be given all the related keywords, may become a reality. This will free the user from having to learn specific rules about searching, allowing energies to be focused on results of the search, not the search itself.