Perhaps you should try some spelling variations:
models studies » model studies, modern studies, modeling studies
die filosofia » di filosofia, de filosofia, e filosofia
e literatura » de literatura, e literatur, a literatura
y literatura » la literatura
test models » trust models, cost models, testing models
studies die » studie die, studien die, studies does

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: test models studies die filosofia ((e literatura) OR (y literatura)).
• Adding a wildcard symbol may retrieve word variants: test models studies die filosofia ((e literatura) or (y literatura))*.