Perhaps you should try some spelling variations:
thanh tung » thanh cong
trong quan » thong quan, tong quan, thong quang
hieu sang » chieu sang, hieu lang, hieu quang
quan phan » quang phan, luan phan, qua phan
doc hieu » toc thieu, hoc thieu, hoc hien
phan cau » phan dau, phan cac, phan tu
va dung » van dung, va duong, vat dung

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 dung trong quan phan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sang - ((thanh trung) OR (thanh tung)) va dung trong quan phan cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu sang - ((thanh trung) or (thanh tung)) va dung trong quan phan cau*.