Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu sang, chieu tinh
thanh tung » thanh cong
hieu lang » chieu sang, hieu quang, nhieu tang
dung cong » dung trong
tung vat » dung vat, tang vat, tung va
vat dung » van dung, va dung, viet dung
tap toan » tap quan, bai toan
tap doan » tap quan

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: ho ((chieu xanh) OR (hieu lang)) - thanh tung vat dung cong ((tap toan) OR (tap doan)) cao~.
• Adding a wildcard symbol may retrieve word variants: ho ((chieu xanh) or (hieu lang)) - thanh tung vat dung cong ((tap toan) or (tap doan)) cao*.