Perhaps you should try some spelling variations:
tinh huong » dinh huong, anh huong
dung lang » dung dang, dung nang, dung land
kien soat » kiem soat, bien soan, kien hoa
hieu suat » hieu luat, hieu qua
lang van » dang van, tang van, hoang van
van kien » van tien, van hien, van chien
van hieu » cao hieu
lam van » lam san, nam van, dam van

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

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