Fair Use allows limited use of copyrighted materials for educational and research purposes. The statute outlines four factors that should be assessed in determining whether a use is a Fair Use. These are:
the purpose and character of your use
the nature of the copyrighted work
the amount and substantiality of the portion taken, and
the effect of the use upon the potential market.
The test is, intentionally, fact dependent, so you need to look at each use individually to determine if it is a fair use.