Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu qua, diep quang
nhung cong » dung cong, thong cong, hang cong
hieu quan » hieu qua, lieu quan, thien quan
hanh tran » hanh trang, thanh tran, hanh tram
van nhung » van nhuong, va nhung, van hung
tran van » luan van
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((hieu quang) or (hieu quan)) - hanh tran van nhung cong san toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu quang) OR (hieu quan)) - hanh tran van nhung cong san toan cau.
• Adding a wildcard symbol may retrieve word variants: theo ((hieu quang) or (hieu quan)) - hanh tran van nhung cong san toan cau*.