Perhaps you should try some spelling variations:
cang thang » cong thanh, dang thanh
hieu lang » chieu sang, hieu quang, nhieu tang
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
ban than » ban thanh, van thanh, ban hang
cong va » dong va, cong ha, cong tac
va dung » van dung, va duong, vat dung

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu lang - thanh cong va dung cong ((ban than) OR (cang thang)) cap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu lang - thanh cong va dung cong ((ban than) OR (cang thang)) cap".
• Adding a wildcard symbol may retrieve word variants: doc hieu lang - thanh cong va dung cong ((ban than) OR (cang thang)) cap*.