Peer-reviewed journals (also called refereed journals) are scholarly journals that publish articles only after they have passed through a strict review process. When an author submits an article to a peer-reviewed journal, the journal editors send it out to other experts in the same field (the author's peers) to get their opinion on the quality of the research and methodology.
You can search for articles from peer-reviewed journals in most of the library databases.
If you use the Library Search box, a tool that allows you to search a majority of the library's physical and electronic resources using one simple search box, just click in the box next to Scholarly (Peer-Reviewed):
In the ProQuest databases, the Peer reviewed option is below the search box: