Perhaps you should try some spelling variations:
quang quang » quan quang, dang quang, dung quang
tinh dung » trinh dung, tin dung, tinh huong
hieu suat » hieu luat, hieu qua
quang van » quang ban, quan van, quang uan
kiem soat » kiem toan
dung lan » dung luan, dung land, dung lam
van hieu » cao hieu
van kiem » va kiem, van kien, van hien
lan van » luan van, lang van, tan 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 lan van hieu suat ) or ( tinh quang quang van kiem soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung lan van hieu suat ) OR ( tinh quang quang van kiem soat )).
• Adding a wildcard symbol may retrieve word variants: (( tinh dung lan van hieu suat ) or ( tinh quang quang van kiem soat ))*.