Search in a multidisciplinary database or one that is discipline-specific using keywords that might appear in titles or abstracts to identify articles that have used qualitative methods. Below is a partial list of terms to try:
Using an asterisk (*) after a term tells the database to search for variant endings of the word. For example, observation* will include results with the terms observation, observations, or observational. Below is an example of a database search.
A small number of databases have filters that include searches by methodologies. In PubMed click on "Additional Filters" on the left side of your search results page and look through the Article Types to see if the methods you are researching are included. APA PsycInfo labels their filter Methodology. On the left side of your search results page, click on Methodology and then Show more to choose methods of interest.
Using Subject Headings
Some databases developers have created standardized terminology so that all items in the database are described with the same words. There are variously called subject headings, descriptors, thesaurus terms, and other similar labels. For example, the nursing database, CINAHL, does not have a methodologies filter, but searching in their list of subject terms will produce a list of relevant subjects to choose from. PubMed, PsycInfo, and other databases have similar lists for their databases. Other databases with standardized vocabularies may also have relevant terms. Check for a thesaurus or searchable list of subject headings to quickly identify words and phrases you can use.