Perhaps you should try some spelling variations:
dung chung » dung cong, dung ung, dung trung
tinh dung » trinh dung, tin dung, tinh quang
hieu suat » hieu luat, hieu qua
kiem soat » kiem toan
dung cua » dung cho
van kiem » va kiem, van kien, van hieu
cu hieu » cua hieu, cuu hieu, co hieu
cua van » cua ban, cua vat, cua dan

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 chung) OR (dung luan)) cu hieu suat ) OR ( tinh dung cua van kiem soat ))~.
• Adding a wildcard symbol may retrieve word variants: (( tinh ((dung chung) or (dung luan)) cu hieu suat ) or ( tinh dung cua van kiem soat ))*.