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

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