Perhaps you should try some spelling variations:
filosofica da » filosofia da, filosofia de, filosofia di
da literatura » la literatura, a literatura, de literatura
studium das » studium des, studium der, studium die
des dualen » der dualen, des idealen
studium ds » studium des, studium d, studium der

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: "des dualen ((studium ds) OR (studium das)) filosofica da literatura*".