Perhaps you should try some spelling variations:
quang tuan » quang thanh, quan luan, quang cua
tinh dung » trinh dung, tin dung, tinh huong
hieu luat » hieu qua
kiem soat » kiem toan
quan han » quan hanh, quanh han, quan hai
quan ha » quan he
tuan va » toan va, luan va, quan va
va kiem » van kien

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 han) OR (quan ha)) hieu luat ) OR ( tinh quang tuan va kiem soat ))~.
• Adding a wildcard symbol may retrieve word variants: (( tinh dung ((quan han) or (quan ha)) hieu luat ) or ( tinh quang tuan va kiem soat ))*.