Perhaps you should try some spelling variations:
thanh tung » thanh cong
hieu sang » chieu sang, hieu lang, hieu quang
dang cong » dung cong
doc hieu » toc thieu, hoc thieu, hoc hien
cong ban » cong bang, cong san, cong tan
ban phan » ban phap, van phan, ban than
phan cau » phan dau, phan cac, phan tu
va dang » van dang, 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: doc hieu sang - ((thanh trung) or (thanh tung)) va dang cong ban phan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sang - ((thanh trung) OR (thanh tung)) va dang cong ban phan cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu sang - ((thanh trung) or (thanh tung)) va dang cong ban phan cau*.