When searching for clinical or research-oriented literature, the PICO acronym helps to frame your question into something searchable.
Let's say for your research topic you are interested in the effect music therapy has on the elderly. If you were to do a basic search for music therapy AND elderly, you'd get way too many results, and they wouldn't be very well focused on any one particular therapy. To help you focus in on the particular aspects of your topic you are most interested in, use PICO to help frame your question. The examples below illustrate how this works:
Question: Does music therapy improve quality of life for the elderly?
||Poplulation, patient, problem
||no music therapy
||quality of life
||Time (not always necessary)
||Phenomenon of interest
By plugging my research question into the PICO framework, it has helped me identify some initial search terms I can use when searching CINAHL:
elderly AND "music therapy" AND "quality of life"
elderly AND "music therapy" AND "nursing homes"