Perhaps you should try some spelling variations:
da literatura » la literatura, a literatura, de literatura
filosofia da » filosofia de, filosofia del, filosofia e
e filosofia » la filosofia
1 studien » 1 studies
1 studie » 1 studies, 3 studie, 11 studies

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: "test ((1 studie) OR (1 studien)) e filosofia da literatura".
• Adding a wildcard symbol may retrieve word variants: test ((1 studie) OR (1 studien)) e filosofia da literatura*.