Perhaps you should try some spelling variations:
studies does » studies dress, studies ds, studies do
a literatura » la literatura, a literature, y literatura
studies der » studies ds, studies d, studies dn
filosofia a » filosofia da, filosofia la, filosofia e
tests case » test case, tests based, test cases

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: "tests case ((studies does) OR (studies der)) filosofia a literatura".
• Adding a wildcard symbol may retrieve word variants: tests case ((studies does) OR (studies der)) filosofia a literatura*.