Academic Info -- Academic subject guides from colleges around the world
BASE -- academic open access resource library, maintained by Bielefeld University Library
ERIC -- Education Resource Information Center, maintained by the U.S. Department of Education
Infomine -- from UC Riverside, excellent directory or academic articles organized by content areas
Infotopia -- safe search, arranged by content areas, evaluate results, most are academic, some are not
Library of Congress --
RefSeek -- carefully evaluate the results; some great resources but not all are "academic"
Virtual Learning Resources -- a portal site, with links recommended by teachers and professors