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.
We used Science Citaiton Index to start. After that, you will want to consult the major subject-specific database 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.
RefWorks can help you keep track of all of your references, link to the full text, and format your papers.