Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
kien soat » kiem soat, bien soan, kien hoa
tinh quan » tinh quang, trinh quan, tin quan
hieu soat » hieu suat, hieu hoat, kiem soat
hieu luat » hieu qua
dung lan » dung luan, dung land, dung lam
van kien » van tien, van hien, van chien
quan san » luan san, quan sat, quan van
lan van » luan van, lang van, tan van
san van » tan van, luan van, tran 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 lan van kien soat ) OR ( tinh quan san van ((hieu soat) OR (hieu luat)) ))~.
• Adding a wildcard symbol may retrieve word variants: (( tinh dung lan van kien soat ) or ( tinh quan san van ((hieu soat) or (hieu luat)) ))*.