Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
thanh tung » thanh cong
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
toan tap » toan ban
ho hieu » ho chieu, hoi hieu, nho hieu
va hang » van hang, va lang, va hanh
va nang » van nang, da nang, cam nang

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

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