Formulate your question:
Before you start searching the literature, you must define your research question and focus it into a searchable question. Doing this makes it easier to identify and combine appropriate search terms. This increases the chances of retrieving relevant results.
One common way to define your question is by using the PICO framework (See Secondary Sources).
Once you have formulated your searchable question and have identified appropriate search terms, the next step is to think of synonyms, i.e. other ways authors may express your search terms.
Terms that have the same meaning:
Terms that have alternate spellings:
Severe Acute Respiratory Syndrome
Umbrella terms and specific conditions
Herpes, gonorrhea, syphilis, etc.
Keywords and database-specific subject headings
Cancer, tumour, tumor, carcinoma
Using AND, OR, NOT (Boolean Operators)
Incorporating Boolean operators into your search strategy will make your search more efficient and allow you to combine multiple search queries into one search.
OR: Combines terms that are the same concept
e.g. teenagers or adolescents or youth
AND: Combines different concepts
e.g. teenagers AND mental health
NOT: Use this when you want to exclude a particular subset of a concept
e.g. mental health NOT depression
NOTE: Use brackets to group concepts together and force an order of operations.
e.g. (teenagers OR adolescents OR youth) AND (mental health OR mental illness) NOT depression
Sometimes it helps to visualize a Venn diagram when using Boolean operators, like the one below.
Keywords and subject headings are combined using OR. Concepts (e.g. P, I, C, O) are combined using AND.