Researchers often need literature to support the background of their main research. You can make use of the various functions in the database to explore and think of research topics and examine the development trends of a research domain, allowing you to avoid wasting time on repeating research.
You can also use the population-intervention-comparison-outcome (PICO) model for general or EBM questions: Formulate a question by cross-searching for known concepts in the research question with "AND" (e.g., diabetes AND cardiovascular), click on Refine Results (post-classification) to show a list of keywords, focus your results to relevant topics such as specific interventions or risk factors, and assess the published articles to identify areas that are more popular or relatively lacking (number of articles).
Databases with "Refine Results" function include Ovid Medline, Embase, EBSCOhost (MEDLINE, CINAHL, and databases for various disciplines) etc., and Web of Science, Scopus, etc. Taking Scopus as an example:
Step 1. Search for articles in the database
Step 2. Click on "View all" below a list of Keyword (or Subject depending on the database used) under Refine Results on the left of the search result
Step 3. Examine the list of keywords and number of results according to your background knowledge and needs and explore the direction on which to focus your research, such as different types of intervention (yellow-highlighted words: exercise, diets, lifestyle, medications) or risk factors (green-highlighted words: metabolic syndrome X, biological marker).
Scopus and Web of Science can analyze search results and produce graphs. Taking Web of Science as example:
Step 1. Search for articles in the database
Step 2. Click on "Analyze Results”
Step 3. Click on "Publication Years", choose "Bar Graph" from the drop-down menu of Visualization, and select Number of Result: 25. Bar graph)