Use your problem statement as an outset to find the key concepts and search terms. After that, you can use dictionaries, encyclopedias and other resources to find useful search terms and synonyms. Also check for keywords while you search. Many databases use controlled vocabulary (subject terms) defined in a thesaurus or subject headings list (for ex. MeSH or CINAHL Subject Headings). MeSH (Medical Subject Headings)
If you are looking for subject terms on emotions, personal experiences, interpersonal relations etc., you can consult this glossary of common subject terms: Subject terms on experiences and interpersonal relations - a glossary from the Library at Karolinska Institutet
Video (6:53). Faculty of Medicine, Lund University.
Search with subject headings for increased relevance
Many databases have their own lists of subject headings that you can use. Subject headings are a form of controlled vocabulary. Searching with controlled vocabulary often provides increased relevance, compared to a free text search. The articles in the databases are tagged with subject headings describing the main focus, which makes it easier for you to find relevant articles.
A free text search, where you search with keywords without using subject headings, becomes a less specific search. The free text search becomes broader and also provides material where your words are mentioned, for example in the abstract, but are not necessarily the essence of the article.
If you are going to conduct a more comprehensive search, for example in a literature study, you may need to combine searching with subject headings with a free text search.
Each database has their own list of controlled vocabulary, that is valid within that database. Examples of that are MeSH (Medical Subject Headings) in PubMed, Emtree in Embase and CINAHL Subject Headings in CINAHL. You can select headings and create your search directly in the database using the subject heading lists.
There may be different words for breast cancer in different articles, for example breast tumor or mammary cancer, but there is a subject heading that every article is tagged with. In this case, breast neoplasms is the MeSH term for breast cancer. If you search with it, you will find all the articles in the database that are relevant in relation to breast cancer no matter what synonym the authors used. At the same time, articles where breast cancer is mentioned but is no significant part of the article are cleared from the result list.
Video (5:17) How to search with Subject Headings combined with text words in the CINAHL database.
Library and ICT, Faculty of Medicine, Lund University.