Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
thanh tinh » thanh binh, nhanh tinh, than kinh
dang cong » dung cong
bang cong » bang song, hang cong, dung cong
tinh cua » trinh cua, sinh cua, tinh chat
toan cao » toan tap
toan ban » van ban
ho hieu » ho chieu, hoi hieu, nho hieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho hieu quang - thanh tinh cua ((dang cong) or (bang cong)) san ((toan cao) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu quang - thanh tinh cua ((dang cong) OR (bang cong)) san ((toan cao) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: ho hieu quang - thanh tinh cua ((dang cong) or (bang cong)) san ((toan cao) or (toan ban))*.