Perhaps you should try some spelling variations:
quan trong » gian trong
hieu lang » chieu sang, hieu quang, nhieu tang
song quan » tong quan, hong quan, uong quan
nho hieu » nha hieu, nho sieu, nhu hieu
cong tan » cong tac, cong san, cong thanh
than cau » toan cau, phan cau, than cap
phan dau » phan tu, hang dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: nho hieu lang - nang song quan trong cong tan ((than cau) or (phan dau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nho hieu lang - nang song quan trong cong tan ((than cau) OR (phan dau))*.