Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu sach, chieu xanh, hieu lang
doi chieu » doc hieu, doi chi, ho chieu
tam dung » tam duong, tan dung, am dung
tac dung » sach dung, xay dung, tin dung
dan toan » van toan, dan than, manh toan
ban than » ban thanh, van thanh, ban hang

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doi chieu sang - thanh trung ((tam dung) OR (tac dung)) cong ((dan toan) OR (ban than)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi chieu sang - thanh trung ((tam dung) OR (tac dung)) cong ((dan toan) or (ban than)) cau~".
• Adding a wildcard symbol may retrieve word variants: doi chieu sang - thanh trung ((tam dung) OR (tac dung)) cong ((dan toan) or (ban than)) cau*.