Google Scholar provides a simple way to broadly search for scholarly literature. From one place, you can search across many disciplines and sources: peer-reviewed papers, theses, books, abstracts and articles, from academic publishers, professional societies, preprint repositories, universities and other scholarly organizations. Google Scholar helps you identify the most relevant research across the world of scholarly research.
The Web of Science covers 5,600 journals from scientific disciplines from 1900 to present. Coverage is limited to top-rated science journals by ISI's methodology; use other in-depth databases on this page for stronger coverage of specific disciplines. Citations include abstracts. Search for articles that cite an author or article or search for articles by subject, author, etc.
EndNote Web is a Web-based service designed to help students and researchers through the process of writing a research paper. [EndNote Web login]
RefWorks -- an online research management, writing and collaboration tool -- is designed to help researchers easily gather, manage, store and share all types of information, as well as generate citations and bibliographies.