Perhaps you should try some spelling variations:
trinh han » trinh quan
hieu suat » hieu qua
hieu luat » hieu qua
dung lang » dung dang, dung nang, dung land
kien soat » kiem soat, bien soan, kien hoa
han hang » hang hang, han chang, ban hang
lang van » dang van, tang van, hoang van
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: (( trinh han hang va ((hieu suat) OR (hieu luat)) ) OR ( tin dung lang van kien soat ))~.
• Adding a wildcard symbol may retrieve word variants: (( trinh han hang va ((hieu suat) or (hieu luat)) ) or ( tin dung lang van kien soat ))*.