Search Basics: Searching the Free Web
Since web pages are not highly structured database fields, the way information is gathered and then search is very different from a library catalog or academic database. Companies like Google and Yahoo! use computer programs, called robots and spiders, to crawl about the web identifying sites, usually looking at URLs, text in each document, and the page title. Learn more about this technique with the Searching the Internet tutorial.
Because of the minimal structure free-text searching is the default and often the only option. There are some stand techniques you can apply to get better search results.
A plus sign requires the word to be present in the web page. This can help focus your search.
Example: finding information about arts funding and the NEA (National Endowment for the Arts)
Type: +arts +funding +nea
A minus symbol excludes pages that have the word or words appearing after the symbol. This can help narrow yours search.
Example: finding information about cloning but not about sheep
Type: cloning -sheep
Quotation marks search for words in the exact order they are typed; also call phrase searching. This technique can also focus your search.
Example: finding information about global warming
Type: "global warming"
Most search engines have an advanced search option where you can apply additional limits or filters. Some common filters include domain (.com, .edu, gov, etc.) and page title. For more information about various search engines, visit the Search Engine Watch and Search Engine Showdown web sites.