Databases use controlled keywords (known as thesaurus or subject terms) to categorize each record stored. PubMed, for example, uses Medical Subject Headings (MeSH), a highly structured index of terminology. The subject headings vary for each database according to their indexing system. The term "qualitative research" is indexed in PubMed as "Qualitative Research" or "Nursing Methodology Research", while in CINAHL the subject heading "Qualitative Studies" is complemented by more detailed terms, including "Phenomenological Research" and "Grounded Theory".
Strategy 2: Use Text Words
This strategy uses text or keywords that might specifically identify qualitative research and searches the titles, abstracts and keywords of records held in the databases. Some Text Words include: qualitative, ethnograph*, phenomenol*, ethnonurs*, grounded theor*, purposive sample, hermeneutic*, heuristic*, semiotics, lived experience*, narrative*, life experiences, cluster sample, action research, observational method, content analysis, thematic analysis, constant comparative method, field stud*, theoretical sample, discourse analysis, focus group*, ethnological research, ethnomethodolog*, interview*.
Strategy 3: Use Qualitative Research Filters
Qualitative Research Filters are pre-formulated search strategies that have been constructed by librarians to help you retrieve articles in databases that deal with qualitative research. You can use the filter and then combine the results with your subject.
Introduction to Qualitative Research Methods by 
Qualitative Research Methods for Psychologists by 
EBOOK: Qualitative Research Methods in Psychology: Combining Core Approaches by 
Qualitative Communication Research Methods by 
Quantitative Research for the Qualitative Researcher by 