Some coursework requires identifying research articles in the PubMed or CINAHL databases. Some assignments call specifically for randomized, controlled clinical trials; some may also allow the inclusion of non-randomized or quasi-experimental, studies.

Both PubMed and CINAHL offer a data element called Publication Type and Randomized Controlled Clinical Trial is an option in both databases.
Narrowing a general search to quasi-experimental studies a bit less straight-forward, since there is no Publication Type for them. In PubMed, there is a MeSH term Non-Randomized Controlled Trials as Topic, which is for quasi-experimental research.  Note that this term has only been used by indexers since 2015. Some quasi-experimental studies are tagged with publications types of Multicenter Study or Comparative Study.

The CINAHL Heading for that type of study is Quasi-experimental Studies.

It may also be helpful to search either database for the phrase "quasi-experimental study" in the titles of articles. In PubMed that would look like this:
"quasi-experimental study"[ti]
with double quotation marks around the phrase.

In CINAHL, change the menu in the search box to Title and type the phrase in double quotation marks.

A document on this topic is pinned below.