Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
hanh dinh » thanh dinh, hinh dinh, hanh tinh
cua nhung » va nhung
trinh san » trinh quan, trinh toan, trinh luan
trinh han » trinh quan
hoi hieu » hoi phieu, hoi tieu, moi hieu
dinh cua » dinh cuu, sinh cua, dinh cu

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 dinh cua nhung cong ((trinh san) OR (trinh han)) dau~.
• Adding a wildcard symbol may retrieve word variants: hoi hieu lang - hanh dinh cua nhung cong ((trinh san) or (trinh han)) dau*.