An Excellent Guide to searching PubMed from the University of North Carolina at Chapel Hill - http://guides.lib.unc.edu/pubmedtentips
You can use Google Scholar (https://scholar.google.com/) as a sort of open database of scholarly articles on your topic. It doesn't replace databases like CINAHL or PubMed, but it can be used in addition.
Linking full text between Scholar and DUC's Databases
If you do a search in Scholar, you can connect the full-text links from our databases to the Scholar results. On the far right of your results, look for the Settings icon, or the small arrow that will reveal the settings.
Click Library Links. Search for Dominican University of California, and check the boxes. It's that easy!
The version we use, EBSCO, is at the 1:50 mark in the video.
Google Scholar offers related articles as well as articles than have cited a particular study. When you search, keep an eye out for the links below the citation.
Qualitative:
Check the Research check box, and use the Clinical Queries menu on the Advanced Search:
Quantitative:
There is no easy way to specify quantitative studies in CINAHL.
Randomized Controlled Trials (check box or in the Publication Type menu) are often quantitative, or at least have a quantitative aspect.
With the Research check box, use the Publication Type menu: