Perhaps you should try some spelling variations:
la literatura » la litterature, a literature
na literatura » a literatura, a literature, y literatura
drugs studie » drugs studies, drugs studied, drug studies
e filosofia » la filosofia
best drugs » obesity drugs
studie e » studie 2, studie _, studie 1

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: "best drugs studie e filosofia ((na literatura) OR (la literatura))".
• Adding a wildcard symbol may retrieve word variants: best drugs studie e filosofia ((na literatura) OR (la literatura))*.