Perhaps you should try some spelling variations:
trinh tung » trinh trung, trinh dung, trinh ung
bien soan » bien so
tinh dung » trinh dung, tin dung, tinh huong
hieu suat » hieu luat, hieu qua
tung dan » dung dan, huong dan, trung dai
van bien » van tien, van hien, vat bien
van hieu » cao hieu
dan van » dang van, doan van, dao van
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 tung dan van bien soan ) or ( ((tinh dung) or (tinh quang)) lam van hieu suat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh tung dan van bien soan ) OR ( ((tinh dung) OR (tinh quang)) lam van hieu suat )).
• Adding a wildcard symbol may retrieve word variants: (( trinh tung dan van bien soan ) or ( ((tinh dung) or (tinh quang)) lam van hieu suat ))*.