Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
hieu soat » hieu hoat, hieu luat, kiem soat
hieu suat » hieu luat, hieu qua
tinh quan » tinh quang, trinh quan, tin quan
quan quan » quan quang, qua quan, quan luan
quan dang » quang dang, quan lang, quan dong
dung dat » dung va, dung tai
dieu hat » dieu hanh, dieu khac, dieu can
dat van » dao van, dat va, dam van

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 dat van ((hieu soat) or (hieu suat)) ) or ( tinh quan quan dang dieu hat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung dat van ((hieu soat) OR (hieu suat)) ) OR ( tinh quan quan dang dieu hat )).
• Adding a wildcard symbol may retrieve word variants: (( tinh dung dat van ((hieu soat) or (hieu suat)) ) or ( tinh quan quan dang dieu hat ))*.