Filters, or "Limits," help narrow your search. They apply a preset search limit that the database has developed for your use.
Some of the most popular filters are:
Unless you read the database's help documents or ask a librarian, you won't really know how the filters work. They may say "date" and you might assume that means date of publication, but it actually means the date it was added to the database.
Filters like peer-reviewed/scholarly are usually applied to all articles in a journal that uses the peer-review process for even just some of their articles. So, you may get articles from that journal that are not peer reviewed!
Be careful using filters— they may warp your search results so that you do not see some of the most clinically relevant evidence!