Perhaps you should try some spelling variations:
la litterature » a literature
et litterature » art literature
di filosofia » la filosofia, e filosofia
a filosofia » la filosofia, e filosofia

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 _ studium ((a filosofia) OR (di filosofia)) ((et litterature) OR (la litterature)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "test _ studium ((a filosofia) or (di filosofia)) ((et litterature) OR (la litterature))".
• Adding a wildcard symbol may retrieve word variants: test _ studium ((a filosofia) or (di filosofia)) ((et litterature) OR (la litterature))*.