QuickSearch lets you search more than 200 databases of Librarian-recommended information sources at one time and links you to the articles that your library has purchased for you.
Google Scholar lets you search the major publishers of scholarly and scientific journals and then links you to the articles that your library has purchased for you.
Start with Science Citation Index. After that, you will want to consult the major subject-specific databases for your researcher from the appropriate discipline-specific guide (See box, above left). Finally, you could use Google Scholar (Advanced Search) for a very broad search.