Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trinh qua » trinh quan, trinh quang, trinh luat
trinh cua » tinh cua, trinh luat, trinh quan
bang cong » dang cong, bang song, hang cong
tren thuc » trien thuc, tron thuc, trinh thuc
nho hieu » nha hieu, nho sieu, nhu hieu
cong tac » cong ty
tren tau » tren may, tren dat, tren thi

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: nho hieu quang - hanh ((trinh qua) OR (trinh cua)) bang cong tac ((tren tau) OR (tren thuc))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "nho hieu quang - hanh ((trinh qua) or (trinh cua)) bang cong tac ((tren tau) OR (tren thuc))~".
• Adding a wildcard symbol may retrieve word variants: nho hieu quang - hanh ((trinh qua) or (trinh cua)) bang cong tac ((tren tau) OR (tren thuc))*.