Many databases indicate whether the article is "academic" or "peer-reviewed" in the full citation. Also, you can limit your search results to "academic journals" or "peer-reviewed," so your results will all be scholarly material.
If this information is not available, another option is to look up the title of journal in a database called Ulrichsweb, which gives publication information on all types of periodicals.
If in doubt, ask a librarian! We'll be glad to help.
Example 1: You can limit your search immediately BEFORE you search.
Example 2: You can limit to "Academic Journals" or "Scholarly Journals" (depending on the database you are in) AFTER you conduct your search, thus filtering your results.