Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
dung quan » dung quang, dung luan, luong quan
hieu luat » hieu qua
hieu suat » hieu qua
quan cau » quang cao, toan cau, quan ha
thi nang » thi cong, ki nang, thi hanh
suat hoi » luat hoi, sat hoi, suat khoa
hoi bien » hoa bien, hoi vien, voi bien
bien so » bien doi

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 quan cau ((hieu luat) or (hieu suat)) ) or ( thi nang suat hoi bien so ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung quan cau ((hieu luat) OR (hieu suat)) ) OR ( thi nang suat hoi bien so )).
• Adding a wildcard symbol may retrieve word variants: (( tinh dung quan cau ((hieu luat) or (hieu suat)) ) or ( thi nang suat hoi bien so ))*.