Perhaps you should try some spelling variations:
studien der » studien des, studie der, studien uber
3 studien » 3 studies, i studien, 2.3 studien
hong than » hong tan, long thanh, hong hai
min hong » amin hong, tin hong, min hyoung
yang yi » yang jui
yang xi » yang jui
der a » der _, der e
a min » a main, a mini, a mine

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((((yang yi) OR (yang xi))) or (yang dean))) or (yang di))a 3 studien der a min hong than ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((((yang yi) OR (yang xi))) OR (yang dean))) OR (yang di))a 3 studien der a min hong than ;*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((((yang yi) OR (yang xi))) or (yang dean))) or (yang di))a 3 studien der a min hong than ;*".