Perhaps you should try some spelling variations:
del litterature » de litterature, des litteratures, et litterature
duales studium » das studium
test duales » test doubles, test rules, test oracles
1 filosofia » e filosofia, a filosofia, _ filosofia
y filosofia » e filosofia, a filosofia, la filosofia

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 ((1 filosofia) OR (y filosofia)) del litterature".
• Adding a wildcard symbol may retrieve word variants: test duales studium ((1 filosofia) OR (y filosofia)) del litterature*.