Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trinh cua » trinh luat, trinh quan, trinh luan
dung cong » dung trong
nhu hieu » nhu hien, nha hieu, nho hieu
tinh cua » sinh cua, tinh chat, tranh cua
van toan » van tuan, van tan, van thanh
ban than » ban thanh, van thanh, ban hang

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: nhu hieu quang - hanh ((trinh cua) OR (tinh cua)) dung cong ((van toan) OR (ban than)) ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "nhu hieu quang - hanh ((trinh cua) OR (tinh cua)) dung cong ((van toan) or (ban than)) ban~".
• Adding a wildcard symbol may retrieve word variants: nhu hieu quang - hanh ((trinh cua) OR (tinh cua)) dung cong ((van toan) or (ban than)) ban*.