http://www.goorulearning.org With Gooru, a free search engine for learning, you can quickly find topic-relevant, standards-aligned resources and organize them into teachable and sharable “collections” — all in one place.
http://www.ipl.org/ - This search engine is a public service organization and a learning/teaching environment. Thousands of students and volunteer library and information science professionals have been involved in designing, building, creating and maintaining the ipl2's collections.
http://www.refseek.com/ - Currently in public beta, RefSeek is a web search engine for students and researchers that aims to make academic information easily accessible to everyone. RefSeek searches more than one billion documents, including web pages, books, encyclopedias, journals, and newspapers.
http://www.encyclopedia.com/ - a source with more than 100 trusted sources, including encyclopedias, dictionaries, and thesauri with facts, definitions, biographies, synonyms, pronunciation keys, word origins, and abbreviations.
http://education.iseek.com/iseek/home.page - is a targeted search engine that compiles hundreds of thousands of authoritative resources from university, government, and established noncommercial providers. It provides time-saving intelligent search and a personal Web-based library to help you locate the most relevant results immediately and find them quickly later.
http://www.infotopia.info/ - an academic search engine accessing websites selected by librarians, teachers & library & educational consortica.
http://www.procon.org- ProCon.org is a nonprofit public charity that has no government affiliations of any kind. Their purpose is to provide resources for critical thinking and to educate without bias. We do not express opinions on our research projects.
http://www.magportal.com/ - a search engine that finds individual articles from many freely accessible magazines by browsing the categories or using the search engine.