Perhaps you should try some spelling variations:
en litterature » et litterature, une litterature, la litterature
test failure » test failures, post failure, heart failure
fast failure » post failure, heart failure, graft failure
filosofia en » filosofia e, filosofia del, filosofia con
studies das » studie das, studies data, studies does
studien das » studie das, studien des, studien der

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((test failure) OR (fast failure)) ((studies das) OR (studien das)) filosofia en litterature.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((test failure) OR (fast failure)) ((studies das) or (studien das)) filosofia en litterature".
• Adding a wildcard symbol may retrieve word variants: ((test failure) OR (fast failure)) ((studies das) or (studien das)) filosofia en litterature*.