Perhaps you should try some spelling variations:
trinh chuan » trinh han, trinh quan, trinh luan
chuan doan » chan doan
tinh dung » trinh dung, tin dung, tinh quang
dung lang » dung dang, dung nang, dung land
hieu luat » hieu qua
lang van » dang van, tang van, hoang van
van hieu » cao hieu
van kien » van hien, van chien
van tien » toan tien, van tuan

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