Perhaps you should try some spelling variations:
lingual literature » language literature, clinical literature, legal literature
lengua literatura » pena literatura, language literature, la literatura
duales studium » das studium
text duales » text dates, text modules
studium la » studium a, studium als, studium das

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: text duales studium la filosofia ((lengua literatura) OR (lingual literature))*.