The following tips are from Maribeth Slebodnik, University of Arizona.
Here are some ideas for searching CINAHL for nursing theories:
Look in the CINAHL thesaurus for Nursing Theory or Theoretical Nursing Models subject headings.
Search for the name of the theory by putting it in quotes, e.g. "Theory of Human Caring" or "Human Caring Theory".
Do an author search for articles written by a specific theorist (e.g. Jean Watson).
Try a focused subject search on the specific theory you need; CINAHL has several subject headings for different theoretical models including Orem Self-Care Model, Roy Adaptation Model, Watson's Theory of Caring, etc.
To really narrow down your search, combine a nursing theory subject heading with another subject heading. For example, if you need information on Orem's theory and patients with cancer, combine the two subject headings of Orem Self-Care Model and Cancer Patients. This may be TOO narrow so be prepared to broaden your search if you end up with no results.
If you are searching PubMed, you can use the same process to find nursing theory articles. The MeSH subject headings in PubMed are Nursing Theory or Nursing Model - combine them with OR plus distinctive words from the theory name for the best results.
Other sources for theory related literature
If you are using a theory that is not from the nursing literature, you may need to look in other databases for relevant articles. You can look in the database thesaurus for subject headings for the theory, or try the theory name in quotation marks as a keyword search.