Perhaps you should try some spelling variations:
e letterature » e letteratura, et litterature, de litterature
test duales » test doubles, test rules, test oracles
filosofia e » filosofia de, filosofia del
studium di » studium die, studium i, studium d
studium ii » studium im, studium i, studium die

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 di) OR (studium ii)) filosofia e letterature".
• Adding a wildcard symbol may retrieve word variants: test duales ((studium di) OR (studium ii)) filosofia e letterature*.