Perhaps you should try some spelling variations:
"tinh dung luan van kien soat" » "trinh dung luan van kien soat", "tin dung luan van kien soat", "tinh quang luan van kien soat", "tinh dung luan van kiem soat", "tinh dung luan van bien soan", "tinh dung luan van kien hoa", "tinh dung luan van tien soat", "tinh dung luan van hien soat", "tinh dung luan van chien soat"
"tinh quan lan van hieu soat" » "tinh quang lan van hieu soat", "trinh quan lan van hieu soat", "tin quan lan van hieu soat", "tinh quan lan van hieu suat", "tinh quan lan van hieu hoat", "tinh quan lan van hieu luat", "tinh quan luan van hieu soat", "tinh quan lang van hieu soat", "tinh quan van van hieu soat", "tinh quan lan cao hieu soat", "tinh quan tan van hieu soat", "tinh quan san van hieu soat"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("tinh dung luan van kien soat") or ("tinh quan lan van hieu soat"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("tinh dung luan van kien soat") OR ("tinh quan lan van hieu soat")).
• Removing quotes may allow a broader search: (( tinh dung luan van kien soat ) or ( tinh quan lan van hieu soat )).
• Adding a wildcard symbol may retrieve word variants: (("tinh dung luan van kien soat") or ("tinh quan lan van hieu soat"))*.