Perhaps you should try some spelling variations:
thanh trung » thanh tung
trung quang » truong quang, trong quang, trung quan
chieu sang » chieu sach, chieu xanh, nhieu tang
quang dung » quang trung, ung dung, cuong dung
hieu lang » hieu quang, nhieu tang, hieu van
dung cong » dung trong
cong san » cong tac
toan cau » toan cao, toan tap, toan tai
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu lang) or (chieu sang)) - thanh trung quang dung cong san ((toan cau) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu lang) OR (chieu sang)) - thanh trung quang dung cong san ((toan cau) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu lang) or (chieu sang)) - thanh trung quang dung cong san ((toan cau) or (toan ban))*.