Never pay for an article you find online!!! If you go to http://scholar.google.com from your personal computer, you will probably be asked to PAY for journal articles. Don't do it!
Access Google Scholar via the library's link, then validate yourself as a UM student. Do your search and you'll see "Availability at UMichigan" links in the results that will bring you to the articles FOR FREE!
Here's how the screen will look if you log in via the library:
See our guide to Academic Research with Google for advanced searching tips and more info on Google Scholar: http://guides.lib.umich.edu/google.
Web of Science searches the top journals in many disciplines. It is a subscription database, so you need to search it through the library's site.
Web of Science has many useful features:
NB: Web of Science searches the article title and sometimes the abstract; it does NOT have a specialized thesaurus like PsycINFO. So, you may miss some articles if you only rely on WOS.