Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
hieu soat » hieu suat, hieu hoat, hieu luat
tinh gian » tinh gia, tinh giao, trinh giang
ban tieng » van tien, ban tinh, va tieng
van hieu » cao hieu
gian cua » gian xu, ban cua
van kiem » va kiem, van kien, van hien
luan » quan, lan

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 hieu soat ) or ( tinh gian cua ((van kiem) or (ban tieng)) soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung luan van hieu soat ) OR ( tinh gian cua ((van kiem) OR (ban tieng)) soat )).
• Adding a wildcard symbol may retrieve word variants: (( tinh dung luan van hieu soat ) or ( tinh gian cua ((van kiem) or (ban tieng)) soat ))*.