Perhaps you should try some spelling variations:
quang tang » quang thang, quang dang, quang tung
tinh dung » trinh dung, tin dung, tinh huong
dung lang » dung dang, dung nang, dung land
hieu suat » hieu qua
hieu luat » hieu qua
kiem soat » kiem toan
lang cao » nang cao, lang co, quang cao
tang van » dang van, hoang van, trong van
van kiem » va kiem, van kien, van hieu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh dung lang cao ((hieu suat) or (hieu luat)) ) or ( tinh quang tang van kiem soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung lang cao ((hieu suat) OR (hieu luat)) ) OR ( tinh quang tang van kiem soat )).
• Adding a wildcard symbol may retrieve word variants: (( tinh dung lang cao ((hieu suat) or (hieu luat)) ) or ( tinh quang tang van kiem soat ))*.