Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
tranh cua » doanh cua, manh cua
trung cua » truong cua, trung tuan, trung cap
dang cong » dung cong
doi hieu » doi chieu, doc hieu, doi hien
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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: doi hieu lang - hanh ((tranh cua) OR (trung cua)) ((nhung cong) OR (dang cong)) dan than cau~.
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - hanh ((tranh cua) or (trung cua)) ((nhung cong) or (dang cong)) dan than cau*.