Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
dung cong » dung trong
dan thanh » dang thanh, danh thanh, ban thanh
hoc hieu » hoc thieu, hoc hien, doc hieu
tinh hat » tinh chat, tinh hai, tinh ha
hat dung » vat dung, dat dung, hai dung
ban hanh » ban hang

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 tinh hat dung cong ((dan thanh) or (ban hanh)) cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh tinh hat dung cong ((dan thanh) OR (ban hanh)) cac*.