Perhaps you should try some spelling variations:
duale studien » duale studium, scale studien, duales studium
duale studie » duale studium, duales studium, dualen studium
filosofia le » filosofia e, filosofia del, filosofia da
filosofia de » filosofia del

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: tests ((duale studie) OR (duale studien)) 1 ((filosofia le) OR (filosofia de)) literatura.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tests ((duale studie) OR (duale studien)) 1 ((filosofia le) or (filosofia de)) literatura".
• Adding a wildcard symbol may retrieve word variants: tests ((duale studie) OR (duale studien)) 1 ((filosofia le) or (filosofia de)) literatura*.