Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, dung cua
trung cap » truong cao, trung tam
cong manh » cong danh, duong manh, cong thanh
hoi hieu » hoi phieu, hoi tieu, moi hieu
toan cau » toan cao, toan ban, toan tai
toan tap » toan ban

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 ((trung cua) OR (trung cap)) nhung cong manh ((toan cau) OR (toan tap))~.
• Adding a wildcard symbol may retrieve word variants: hoi hieu lang - hanh ((trung cua) or (trung cap)) nhung cong manh ((toan cau) or (toan tap))*.