In many of the library databases, you can limit to academic or peer-reviewed journal articles. Typically, there is a box that you can click that says "(Scholarly) Peer-reviewed." This box is generally located on the left-hand side of the webpage or in the middle of the advanced search page.
In OneSearch!, there are 2 ways to limit to research articles. Watch this short video  to see how to do it.
One word of caution. In most cases, the software will retrieve research articles. However, it is software, so it isn't perfect. A quick librarian tip to see if it's research.....look for references or footnotes. Generally, if it has references, it's considered research.
If you have questions, ask a librarian. We'd be happy to help!