Perhaps you should try some spelling variations:
thanh trung » thanh tung
khong dung » phuong dung, cuong dung, cong dung
thong dung » thong cong, thong thuong
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, trung cap
than cau » toan cau, phan cau, than cap
toan tap » toan ban
he hieu » he nhieu, he dieu, de hieu

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: he hieu lang - thanh trung cua ((khong dung) OR (thong dung)) dan ((than cau) OR (toan tap))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "he hieu lang - thanh trung cua ((khong dung) OR (thong dung)) dan ((than cau) or (toan tap))~".
• Adding a wildcard symbol may retrieve word variants: he hieu lang - thanh trung cua ((khong dung) OR (thong dung)) dan ((than cau) or (toan tap))*.