Perhaps you should try some spelling variations:
duale studies » duale studien, scale studies, duale studium
dd filosofica » di filosofia, de filosofia, da filosofia
la literatura » la litterature, a literature
best duale » best deal, best deals, best scale

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: best duale studies ((dd filosofica) OR (la filosofia)) la literatura.
• Adding a wildcard symbol may retrieve word variants: best duale studies ((dd filosofica) or (la filosofia)) la literatura*.