Perhaps you should try some spelling variations:
della literatura » della letteratura, pela literatura, nella letteratura
der filosofia » de filosofia, e filosofia, da filosofia
testing drug » testing during, testing data
di filosofia » la filosofia, e filosofia
drug studie » drug studies, drugs studies, drugs studied

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 drug studie ((der filosofia) OR (di filosofia)) della literatura".
• Adding a wildcard symbol may retrieve word variants: testing drug studie ((der filosofia) OR (di filosofia)) della literatura*.