The best way to find quantitative studies or qualitative studies is to start your search in a healthcare database, then either limit it by experimental terms or add them to your search topic.
QUALITATIVE STUDIES: You can add "qualitative" to any search. For example, I did a seach in CINAHL, a major database of nursing journals, for the terms: caregivers AND dementia AND qualitative.
See a few results below - even the ones that don't have "qualitative' in the title have other terms used in qualitative study research designs, such as "experiences", "perspectives" and "phenomological".
QUANTITATIVE STUDIES: Although you can add "quantitative" to a topic you are searching, it won't always work because quantitative studies are very common, especially for therapy articles, so the word may not be mentioned. In CINAHL, you can limit your search results to Randomized Controlled Trials from the Advanced Search screen. Scroll down under Limit Your Results and check the Randomized Controlled Trials box. In the example I below, there were more articles found than just using the word quantitative added to the search.
