Google Scholar is pretty amazing. It will search only text and websites from .edu or published scholarly articles. The results will pull up a mixture of full text articles and subscription-only articles. For a university student whose school gives access to subscription sites- this is the best thing ever. For the rest of us, it can be challenging to find the full text of an article. Some subject areas are much better than others. For instance, research about education is pretty open. However, the sciences are pretty limited.
My suggestion is to go and try out the types of searches you would have a tendency to use and see what the availability is.
Red Box: Toggle between academic documents or legal documents.
Turquoise Boxes: Lets you know what kind of an article it is: book, citation, pdf, etc.
Yellow Box: If there is a full text (html, pdf, etc) of the article, the type of text will appear to the side here.
Black Box and Arrow: Clicking this button will generate a automatic citation of the article for your reference section.
Pink Box: Get email notifications if someone cites your article in Google Scholar- If you have published works, fill in the required fields, link your work to you and get updates when people cite your articles.
Green Box: Set criteria and receive an email notification when a new article is added to Google Scholar that meets your criteria. Keep up with the very latest research in the fields you are interested in.