Perhaps you should try some spelling variations:
de litterature » la litterature, et litterature
di filosofia » la filosofia, e filosofia
case studies » case study
d filosofia » de filosofia, da filosofia, e filosofia
texts case » texts cases, text case, texts based

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: "texts case studies ((d filosofia) OR (di filosofia)) de litterature".
• Adding a wildcard symbol may retrieve word variants: texts case studies ((d filosofia) OR (di filosofia)) de litterature*.