Perhaps you should try some spelling variations:
a literatura » la literatura, a literature, y literatura
cost models » cost model
filosofia a » filosofia da, filosofia la, filosofia e
studium la » studium als, studium das, studium _
studium a » studium am, studium ad, studium _

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: "cost models ((studium la) OR (studium a)) filosofia a literatura".
• Adding a wildcard symbol may retrieve word variants: cost models ((studium la) OR (studium a)) filosofia a literatura*.