Perhaps you should try some spelling variations:
la literatura » la litterature, a literature
filosofia la » filosofia da, filosofia le, filosofica da
test items » test systems
studie der » studium der
studie di » studie die, studie d, studie de

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 items ((studie di) OR (studie der)) filosofia la literatura.
• Adding a wildcard symbol may retrieve word variants: test items ((studie di) or (studie der)) filosofia la literatura*.