Empirical research is published in scholarly, peer-reviewed journals and in books. Some library databases do not have a straightforward way to limit to empirical research.
PsycINFO includes a Methodology filter to limit results to empirical research studies.
How to do it:
Type your keywords into the search boxes, as below, and click Search:
At the results page, under Refine Results, scroll down to Methodology and click the box next to Empirical Study:
Search results will update after you check the box next to empirical study. You may also want to limit by publication date or source type.