Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
hieu quan » hieu qua, lieu quan, thien quan
hanh hang » thanh hang, hang hang, hanh han
cong san » cong tac
san chan » san chang, dan chan, san chay
chan cao » chan cho, chat cao, chay cao

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 lang) or (hieu quan)) - hanh hang va nhung cong san chan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoi ((hieu lang) OR (hieu quan)) - hanh hang va nhung cong san chan cao.
• Adding a wildcard symbol may retrieve word variants: hoi ((hieu lang) or (hieu quan)) - hanh hang va nhung cong san chan cao*.