Perhaps you should try some spelling variations:
suitable studie » suitable source
test suitable » best suitable, most suitable, notes suitable
die filosofia » di filosofia, e filosofia, da filosofia
de filosofia » e filosofia, di filosofia, la filosofia
a literatura » la literatura, a literature, y literatura

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 suitable studie ((die filosofia) OR (de filosofia)) a literatura*".