Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh huong
dung quan » dung quang, dung luan, luong quan
hieu suat » hieu luat, hieu qua
quang tan » quang tuan, quang tran, quang toan
kien soat » bien soan, kien hoa, dien hoat
kiem soat » kiem toan
quan vi » quan li, quan tri, quan doi
vi hieu » vi dieu, va hieu, vo hieu
tan van » tran van, tang van, luan van

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung quan vi hieu suat ) OR ( tinh quang tan van ((kien soat) OR (kiem soat)) ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung quan vi hieu suat ) or ( tinh quang tan van ((kien soat) OR (kiem soat)) ))~".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung quan vi hieu suat ) or ( tinh quang tan van ((kien soat) OR (kiem soat)) ))*.