Most libraries subscribe to various types of periodicals, such as scholarly (some of which may be peer-reviewed), popular, or trade publications. Choosing which to use depends on your topic, the type of writing you are doing, your assignment, and the sources your professor wants you to use. Many databases offer the option to limit to "Scholarly/Academic Journals" or "Peer Reviewed". If you're not sure if a journal is considered peer-reviewed, check Ulrich's by looking up the title of the journal.
What is a peer-reviewed journal?
A scholarly journal is peer-reviewed when there is an editorial board that decides which articles should be included for publication. These journals are generally thought to be of the highest quality. To determine if a journal is peer reviewed, look for an editorial board in the early pages or on the journal's website.
To find out if a journal is considered Refereed/Peer-Reviewed, check the Ulrich's database by doing a search for the title of the journal. Many library research databases accessible allow searches to be limited to articles published in Scholarly/Academic as well as Peer-Reviewed journals. Keep in mind not all scholarly journals are refereed/peer-reviewed.