Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
trong san » trong cac, cong san, dong san
dung cong » dung trong
tan thanh » tran thanh, tang thanh, toan thanh
thanh cac » hanh cac, thanh bac, thanh ca
doc hieu » toc thieu, hoc thieu, hoc hien
cong tan » cong tac, cong san, cong thanh

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 ((trong san) or (thong xay)) dung cong tan thanh cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - thanh ((trong san) OR (thong xay)) dung cong tan thanh cac*.