Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
dung land » dung luan, dung lam, dung san
hieu suat » hieu luat, hieu qua
kien soat » kiem soat, bien soan, kien hoa
land van » lang van, lan van, luan van
van hieu » cao hieu
han doan » chan doan, tan doan, chuan doan
van doan » van doanh, van toan, van hoan
van kien » van tien, van hien, van chien

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