Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
dung suat » ung suat, dung luat, dung quat
hieu hoat » hieu hoa, thien hoat, hieu luat
quang uan » quang tuan, quang ban, quang tran
hieu soan » hieu toan, hieu suat, hieu van
quan cua » quan luan, ban cua, gian cua
van hieu » cao hieu
suat va » xuat va
va hieu » va dieu, va hien, cao hieu

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 suat va hieu hoat ) or ( tinh ((quang uan) or (quan cua)) van hieu soan ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung suat va hieu hoat ) OR ( tinh ((quang uan) OR (quan cua)) van hieu soan )).
• Adding a wildcard symbol may retrieve word variants: (( tinh dung suat va hieu hoat ) or ( tinh ((quang uan) or (quan cua)) van hieu soan ))*.