You can limit your searches in several ways:
Search within a site or domain - type .edu
Use flexible vocabulary - if one phrase or combination of words doesn't work, perhaps another will.
Limit by Language, etc.
BEWARE: Always remember to evaluate the quality of the site you are viewing. Don't believe everything you read unless the information comes from a reputable or reliable source.
Evaluation of Resources (University of California, Berkeley)
Power Tips (Tech Insider) - Video (about 2 minutes)