Perhaps you should try some spelling variations:
truong trung » tieng trung
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
tranh cua » doanh cua, manh cua
thanh cac » hanh cac, thanh bac, thanh ca
than cap » khan cap, thanh lap, than cua
ho hieu » ho chieu, hoi hieu, nho hieu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ho hieu lang - canh tranh cua ((nhung cong) or (truong trung)) dan ((than cap) or (thanh cac))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - canh tranh cua ((nhung cong) OR (truong trung)) dan ((than cap) OR (thanh cac)).
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - canh tranh cua ((nhung cong) or (truong trung)) dan ((than cap) or (thanh cac))*.