Perhaps you should try some spelling variations:
nhanh tinh » nhanh thanh, hanh trinh, nhan sinh
cong trong » cong thuong, duong trong, dung trong
hieu lang » chieu sang, hieu quang, nhieu tang
hoi hieu » hoi phieu, hoi tieu, moi hieu
tinh cua » trinh cua, sinh cua, tinh chat
san toan » dan toan, manh toan, xuan toan
van toan » van tuan, van tan, van thanh

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: hoi hieu lang - nhanh tinh cua ((cong trong) OR (cong trinh)) ((san toan) OR (van toan)) tap~.
• Adding a wildcard symbol may retrieve word variants: hoi hieu lang - nhanh tinh cua ((cong trong) or (cong trinh)) ((san toan) or (van toan)) tap*.