Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
dung quan » dung quang, dung luan, luong quan
hieu suat » hieu luat, hieu qua
quang cua » quang tuan, quang huy, dung cua
tien soat » trien hoat, thien hoat, kiem soat
quan cua » quan luan, ban cua, gian cua
van tien » toan tien, van hieu, van tuan
quan ha » quan he
ha hieu » nha hieu, va hieu, phan 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 quan ha hieu suat ) or ( tinh ((quang cua) OR (quan cua)) van tien soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung quan ha hieu suat ) OR ( tinh ((quang cua) OR (quan cua)) van tien soat )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung quan ha hieu suat ) or ( tinh ((quang cua) OR (quan cua)) van tien soat ))".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung quan ha hieu suat ) or ( tinh ((quang cua) OR (quan cua)) van tien soat ))*.