Perhaps you should try some spelling variations:
thanh truong » thanh trung, thanh thuong, thanh tung
hieu quang » thieu quang, hieu quan, hieu qua
hieu sang » chieu sang, hieu lang, nhieu tang
truong va » truong dai, truong cao, truong dao
cong dan » cong san, huong dan, cong dong
cong tan » cong tac, cong san, cong thanh
than cau » toan cau, phan cau, than cap
va bang » va nang, va lang, va ban

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: doc ((hieu sang) OR (hieu quang)) - thanh truong va bang ((cong dan) OR (cong tan)) than cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) or (hieu quang)) - thanh truong va bang ((cong dan) OR (cong tan)) than cau~".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu quang)) - thanh truong va bang ((cong dan) OR (cong tan)) than cau*.