Perhaps you should try some spelling variations:
thanh tuong » thanh thuong, thanh tung, thanh huong
tuong quang » truong quang, thuong quang, luong quang
quang dung » quang trung, ung dung, cuong dung
hieu lang » chieu sang, hieu quang, nhieu tang
dung cong » dung trong
doi hieu » doi chieu, doc hieu, doi hien
cong tan » cong tac, cong san, cong thanh
toan cao » toan ban, toan tap

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 hieu lang - thanh tuong quang dung cong tan ((toan cao) OR (van ban))~.
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - thanh tuong quang dung cong tan ((toan cao) or (van ban))*.