Perhaps you should try some spelling variations:
del litterature » de litterature, des litteratures, et litterature
studien die » studie die, studien der
studien de » studien der, studien des, studien dd
testo » test, tests, texto

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: "testo duale ((studien de) OR (studien die)) filosofia del litterature".
• Adding a wildcard symbol may retrieve word variants: testo duale ((studien de) OR (studien die)) filosofia del litterature*.