Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu quang » thieu quang, hieu qua, diep quang
hieu quan » hieu qua, lieu quan, thien quan
hang cong » dang cong, hang nong, bang cong
quang cao » nang cao, quang nam
trung va » truong va, trang va, trung ha
cong san » cong tac
juan cao » toan cao, quan cau, juan a
va hang » van hang, va nang, va lang

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((hieu quang) or (hieu quan)) - thanh trung va hang cong san ((juan cao) OR (quang cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((hieu quang) OR (hieu quan)) - thanh trung va hang cong san ((juan cao) OR (quang cao)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi ((hieu quang) or (hieu quan)) - thanh trung va hang cong san ((juan cao) OR (quang cao))".
• Adding a wildcard symbol may retrieve word variants: doi ((hieu quang) or (hieu quan)) - thanh trung va hang cong san ((juan cao) OR (quang cao))*.