Increasingly systematic reviews are attempting to deal with much broader topics, including topics allied to medicine but also topics outside of medicine.
If the focus of your systematic review is to find qualitative research, you may be looking for studies:
Examples of qualitative research are:
If you are unsure of the type of research you are looking at, some key techniques which are used in qualitative research are: interviews, focus groups, observation, open-ended questionnaires, surveys, case studies, discourse analysis and textual analysis.