Perhaps you should try some spelling variations:
testing drugs » testing drug, existing drugs, acting drugs
drugs studied » drugs studies, drug studies, groups studied
e filosofiche » ve filosoficke, e filosofica, e filosofia
e filosofie » en filosofie, e filosofia, e filosofi
literatur » literature

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: "testing drugs studied ((e filosofiche) OR (e filosofie)) e literatur".
• Adding a wildcard symbol may retrieve word variants: testing drugs studied ((e filosofiche) OR (e filosofie)) e literatur*.