Examples of filters in biomedical databases:
Article/Document Types: Review, Randomized Controlled Trial, Practice Guideline, etc.
Publication Date
Age
Funding Agencies
Languages
Most databases have controlled vocabulary/subject headings.
Allows focus and precision
For a comprehensive search use keywords as well
Called MeSH in Medline/PubMed
Image source: guides.temple.edu/content.php?pid=1805&sid=1150348
