search

http://en.wikipedia.org/wiki/List_of_search_engines

http://en.wikipedia.org/wiki/List_of_web_directories

http://en.wikipedia.org/wiki/List_of_academic_databases_and_search_engines

http://en.wikipedia.org/wiki/Category:Full_text_scholarly_online_databases

http://en.wikipedia.org/wiki/Category:Bibliographic_databases

http://en.wikipedia.org/wiki/List_of_digital_library_projects

http://en.wikipedia.org/wiki/Outline_of_search_engines