In addition to keywords, there are many other ways to limit your search. In an advanced search in CINAHL (Before you click search), you'll see a lot of options scrolling down the page. Here are some of the important ones.
Journal Subset:
This option allows you to restrict to Nursing jounal collections only.
Geographic Subset:
Restricts you to a geographic locale, like the United States. This controls the location where journals are PUBLISHED, so you'll still get overseas topics and authors.
Evidence-Based Practice:
This restricts to all articles based on observable data, frequently quantitative research studies. These tend to be peer-reviewed by default.
Published Date:
Here are some other useful limiters:
