Searching the World Wide Web
The OWL at Purdue- Searching the Word Wide Web
UC Berkeley Library Tutorial - Finding Information on the Internet
Advanced Google Searches:
Search Engines
The Search Engine List - comprehensive list of major and minor search engines with links and abstracts describing each of the search engines.
15 Most Popular Search Engines, March 2015
Meta Search Engines (search engines that compile information from several search engines)
Search "The Invisible Web" aka "The Deep Web"
The invisible web is information on the web tha cannot be found with general search engines like Google or Yahoo.
How to Mine the Invisible Web: The Ultimate Guide
Deep Web Search - A How-to Site
Some Invisible Web Search Engines
Catalog of US Governemnt Publications
Science.gov, Gateway to U. S. Federal Science
WolframAlpha, Computational Knowledge Engine