Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
hang cong » dang cong, hang nong, bang cong
hoi hieu » hoi phieu, hoi tieu, moi hieu
mang vua » mang cua, mang va, hang va
cong tan » cong tac, cong san, cong thanh
dang va » dang van, dang vat, hang va
tan van » tran van, tang van, luan van

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoi hieu quang - hanh ((dang va) or (mang vua)) hang cong tan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoi hieu quang - hanh ((dang va) OR (mang vua)) hang cong tan van ban*.