There are a few ways to do this, depending on where you are searching.
If you are using PsycINFO, you can limit to methodology in the advanced search using the Methodology filter:

Most databases do not include an option to directly limit to a particular methodology, but it's still possible to limit to articles to a particular methodology by adding it as a keyword or subject term. So for example, if you are looking for empirical studies, you can use these as keywords:
- methodology (or method)
- empirical
- findings
- results
- participants
- qualitative or quantitative
Or if you are looking for systematic reviews or review articles, you can use these as keywords.
TIP: Try changing the search parameter to in Abstract when searching for studies using a particular methodology. So if you're looking for articles using a phenomenological approach, your search might look like this:

Some databases also include methodologies as subjects in the thesaurus, such as CINAHL Complete, MEDLINE Complete, ERIC or Education Source and others.
For example, in ERIC or Education Source the following subject terms for various methodologies come from the thesaurus in the database.
- Participatory research
- Mixed methods research
- Evaluation research
- Action research
- Qualitative research
- Grounded theory
- Quasiexperimental design
- Critical theory
- Ethnography
- Phenomenology
Example:

Once you find the term in the thesaurus, check mark the box and then click Add.