A note: This is only a suggestion on how to locate some types of research.
It is up to the researcher to confirm the study type in the Methods section of any article.
'Experimental Studies' includes:
clinical trials, community trials, controlled before-after studies, double-blind studies, factorial design, historically controlled studies, interrupted time series analysis, nonrandomized trials, one-shot case studies, pretest-posttest, single-blind, solomon four-group design, static group comparison, triple-blind studies. (You can Google these for a definition!)
Qualitative Studies includes:
Action research, ethnographic research, ethnological research, ethnonursing research, grounded theory, naturalistic inquiry, and phenomenological research.
One type of unobtrusive research is content analysis.
Evaluation Research includes:
Formative evaluation research and summative evaluation research.