Perhaps you should try some spelling variations:
a literatura » la literatura, a literature, y literatura
tests acute » testis acute, testing acute, tests active
studien der » studenten der
filosofia a » filosofia da, filosofia la, filosofia e
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: "tests acute ((studien der) OR (studie der)) filosofia a literatura".
• Adding a wildcard symbol may retrieve word variants: tests acute ((studien der) OR (studie der)) filosofia a literatura*.