Ebrary offers an increasing selection of more than 20,000 e-books in business, economics, computers, engineering, and technology.
Questia Digital Library: Questia is the online library that provides 24/7 access to the world's largest online collection of over 67,000 books and 155,000 journal articles in the Physics, Chemistry, Humanities and Social Sciences.
Free Online Books: Listing more than 35,000 English works in various formats.
While searching the database for your required books by author, title or subject.
While searching database for your required books by author, title or subject, use keywords i.e.Math, Calculus, Geography, Electrical Engineering, Physics etc.