Science Direct
http://www.sciencedirect.com/
Science Direct is Elsevier’s leading information solution for researchers, teachers, students, health care professionals and information professionals . It combines authoritative, full-text scientific, technical and health publications with smart, intuitive functionality so that you can stay informed in your field, and can work more effectively and efficiently. It hosts over 12 million pieces of content from 3,500 academic journals and 34,000 e-books