Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, nhieu tang
thanh tung » thanh cong
hieu lang » hieu quang, nhieu tang, hieu van
cong tan » cong san, cong thanh, cong ty
cong tac » cong ty
toan tap » toan ban
tung va » trung va, tuong va, dung va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((chieu sang) OR (hieu lang)) - thanh tung va nhung ((cong tan) or (cong tac)) toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu sang) OR (hieu lang)) - thanh tung va nhung ((cong tan) OR (cong tac)) toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sang) OR (hieu lang)) - thanh tung va nhung ((cong tan) or (cong tac)) toan tap".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) OR (hieu lang)) - thanh tung va nhung ((cong tan) or (cong tac)) toan tap*.