Perhaps you should try some spelling variations:
modell studien » model studies, models studies, moderne studien
le literatura » la literatura, de literatura, de litteratura
e literatura » de literatura, y literatura, e literatur
test modell » tekst modell, test models, test model

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 modell studien _ filosofia ((le literatura) OR (e literatura))".
• Adding a wildcard symbol may retrieve word variants: test modell studien _ filosofia ((le literatura) OR (e literatura))*.