Perhaps you should try some spelling variations:
"tin dung luan trien viec dat" » "tin dung luan thiet viec dat", "tin dung luan tieu viec dat", "tin dung quan tren viec dat", "tin dung luan trien viet dat", "tin dung luan thien viet dat", "tin dung luan tien viet dat", "tin dung luan trien vien dai", "tin dung luan trien vien da", "tin dung luan trien viec lam"
"tinh dung co gian hieu luat" » "trinh dung co gian hieu luat", "tinh quang co gian hieu luat", "tinh huong co gian hieu luat", "tinh dung co gian viet luat", "tinh dung co van hieu luat", "tinh dung co tin hieu luat", "tinh dung co gian hieu qua", "tinh dung cho gian hieu luat", "tinh dung cong gian hieu luat", "tinh dung cua gian hieu luat", "tinh dung con gian hieu luat", "tinh dung co giao hieu luat", "tinh dung co gia hieu luat"

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 co gian hieu luat") or ("tin dung luan trien viec dat"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("tinh dung co gian hieu luat") OR ("tin dung luan trien viec dat"))*.
• Removing quotes may allow a broader search: (( tinh dung co gian hieu luat ) or ( tin dung luan trien viec dat ))*.