Why should I use web sites?
How do I find good web sites?
Start by reviewing the Web Searching Guide for expert advice on the best search engines--both general and specialized.
Of particular note are the "academic web resources" which includes a link to Google Scholar and other search engines that focus on, credible, scholarly information available on the Web.
note: no single search engine comes close to indexing all of the Web.
For every major, most minors, and other special topics, librarians have put together a subject guide with links to quality sites (look for a Web Resources page).