Once you have clarified your clinical question, you need to identify relevant studies from a number of different sources that may be able to answer it.
There are many databases available that collect together published research papers on selected disciplines (e.g. education; engineering; chemistry; nursing; medicine; etc.).
When answering clinical questions, the 3 main databases used for general medical queries are Medline (the primary component of PubMed), Embase and the Cochrane Library. However, there are other databases which may also be appropriate to search, depending on the exact nature of your query, so resources such as PsychInfo (for mental health/psychology); CINAHL (for nursing), etc., may be useful too.
To find out which databases are available for use in your institution, consult your Library or Information Services staff, who should be able to advise and provide details on how to gain access and undertake a literature search.
Your search needs to identify:
Studies of an appropriate design to answer the question, whether it be systematic reviews of RCTs, RCTs, cohort studies, studies assessing adverse effects; see Search strategies for example search filters used to retrieve specific study types.
Studies assessing the relevant PICOT (Population, Intervention, Comparison, Outcome, and Time frame) to answer your clinical question; see Case study of a search.