PubMed provides a variety of tutorials to help improve your search results.
Review articles summarize research to date in a given field. They are based on literature reviews. They can help you:
As such they can be a good place to get an overview of a topic.
See this page from the University of Texas at Austin for more information.
Look for a Publication Type filter in the database you are searching and select Review to limit your results to Review Articles only.
This page is based in large part on Elizabeth Bass' Background Sources for Health and Medical Reporting handout.