Once you've searched all your keywords, you will need to combine your search results. To do this:
APA PsycInfo allows you to limit by a variety of variables including age group, publication year, publication type, language, etc. This helps you narrow down your results.
Choose the "Additional Limits" icon from the main search page and review the many options available.
Once you have finished setting your limits, choose the "Limit A Search" icon found at the top and bottom of the screen.
Looking specifically for empirical research, a literature review, or a clinical case study?
Go to the Methodology menu and choose your preferred methodology.
This video illustrates how to limit to Literature Reviews and Meta Analysis but you can apply the same startegy to limit to Empirical Studies.
APA PsycInfo includes references to all sorts of materials including journal articles, book chapters, conference proceedings, dissertations, etc.
To limit to only peer-reviewed articles, choose Peer Reviewed Journal in the Publications Types menu or in the initial list of major Limits.
The Age Groups limiters allows you to narrow your research to a specific age grouping such as children, seniors, etc.