Perhaps you should try some spelling variations:
der filosofica » de filosofia, e filosofica, e filosofia
drugs studied » drugs studies, drug studies, brass studied
da literatura » a literatura, de literatura, na literatura
la literatura » la litterature, a literature
studied der » studie der, studien der, studies der
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 ((da literatura) OR (la literatura))*".