Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
doi hieu » doi chieu, doc hieu, doi hien
tranh va » tranh van, trang va, trinh va
cong tan » cong tac, cong san, cong thanh
tan toan » tan tran, tap toan, van toan
toan cau » toan cao, toan ban, toan tap

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 - canh ((tranh va) OR (hang va)) nhung cong tan toan cau~.
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - canh ((tranh va) or (hang va)) nhung cong tan toan cau*.