Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
cua thong » cua thuong, cua khong, cua tong
trinh san » trinh quan, trinh toan, trinh luan
trinh han » trinh quan
hoi hieu » hoi phieu, hoi tieu, moi hieu
hanh ban » thanh ban, hang ban, hanh san
ban cua » ban 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: hoi hieu lang - hanh ban cua thong cong ((trinh san) OR (trinh han)) dau~.
• Adding a wildcard symbol may retrieve word variants: hoi hieu lang - hanh ban cua thong cong ((trinh san) or (trinh han)) dau*.