Perhaps you should try some spelling variations:
hanh trang » thanh trung, canh tranh, hanh trinh
hieu lang » chieu sang, hieu quang, nhieu tang
cua thong » cua thuong, cua khong, suat thong
hoc hieu » hoc thieu, hoc hien, doc hieu
cua tong » cua cong, cua dong, cua nong
cong san » cong tac
san van » tan van, luan van, tran van

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu lang - hanh trang ((cua thong) or (cua tong)) cong san van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh trang ((cua thong) OR (cua tong)) cong san van ban.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - hanh trang ((cua thong) or (cua tong)) cong san van ban*.