Perhaps you should try some spelling variations:
quang quan » quang tuan, quang uan, quan quan
tinh dung » trinh dung, tin dung, tinh huong
dung lang » dung dang, dung nang, dung land
hieu suat » hieu luat, hieu qua
kien soat » kiem soat, kien hoa, dien hoat
bien soan » bien so
lang van » dang van, tang van, hoang van
van hieu » cao hieu
quan van » luan van, quan va, quan luan

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 lang van hieu suat ) OR ( tinh quang quan van ((kien soat) OR (bien soan)) ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung lang van hieu suat ) or ( tinh quang quan van ((kien soat) OR (bien soan)) ))~".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung lang van hieu suat ) or ( tinh quang quan van ((kien soat) OR (bien soan)) ))*.