Perhaps you should try some spelling variations:
drugs studied » drugs studies, drug studies, groups studied
filosofica e » filosofica da, filosofia de, filosofia _
studied der » studie der, studien der, studies der
filosofia e » filosofia de, filosofia del
test drugs » best drugs, test drug, tests drug

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "test drugs studied der ((filosofica e) OR (filosofia e)) literatura*".