Perhaps you should try some spelling variations:
de literatuur » de literatura, en literatuur, de litterature
filosofia de » filosofia del
test duales » test doubles, test rules, test oracles
studium ad » studium a, studium d, studium band
studium am » studium im, studium als, studium das

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 duales ((studium ad) OR (studium am)) filosofia de literatuur".
• Adding a wildcard symbol may retrieve word variants: test duales ((studium ad) OR (studium am)) filosofia de literatuur*.