Perhaps you should try some spelling variations:
de litterature » la litterature, et litterature
filosofica de » filosoficas de, filosofia de, filosofica da
studium das » studium des, studium der, studium die
studium ds » studium des, studium d, studium der

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: (test OR text) doubles ((studium ds) OR (studium das)) filosofica de litterature.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(test or text) doubles ((studium ds) OR (studium das)) filosofica de litterature".
• Adding a wildcard symbol may retrieve word variants: (test or text) doubles ((studium ds) OR (studium das)) filosofica de litterature*.