Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
trung cua » truong cua, trung tuan, trung cap
cua dung » cua dang, cua dong, qua dung
cong tac » cong ty
toan cau » toan cao, toan ban, toan tap

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

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