The ERIC database uses a set of specific terms to name the various types of research methodolgies. These terms can be found using the thesaurus.
The simplest way to find article that use a specific research methodology is to add the methodology as a keyword to your search. If possible, determine what term the database uses to name your methodology (see the right and left-hand bars for suggestions). The screen shot below shows an example search for phenomenological studies on learning communities:
Other databases use their own thesaurus of specific terms. These are the terms that ProQuest Education Journals uses for research methodologies.