Searching the Web | search engines
Search engines employ "spiders" or "robots"; that crawl electronically to collect web sites (e.g. google.com or Ask Jeeves) and then add them to their catalog. Using a search engine is similar to searching the index of a book. The searcher enters a word and the engine retrieves records with key words or phrases matching the term entered. Although valuable for locating obscure information, keyword searching can result in large unwieldy lists and may retrieve terms out-of-context.
For example, a search using the term "nursing" may retrieve sites related to nursing as a professional discipline as well as sites selling uniforms.
Each search engine has its own rules for determining how sites are collected and arranged and how search results are ranked according to relevance. Some rank based on frequency of occurrence in retrieved documents; others rank based on how frequently a site is linked from other sites. Sites that describe how search engines work and compare the features of search engines can provide helpful information (see links below).
Search engines have different rules for entering a search string, using boolean connectors, use of quotation marks for phrases, truncation symbols, etc.
Some search engines also include a subject directory of the included sites. Look for the "help" link on the search engine home page to determine how to enter a search.
Searchers should always consider using several search tools because no one search engine covers the entire contents of the web.
Links
- Bobst Library Boolean Tutorial: http://library.nyu.edu:8000/research/tutorials/boolean/boolean.html
