Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, hieu lang
hieu quang » thieu quang, hieu quan, hieu qua
cong thanh » dong thanh, cong trinh, truong thanh
anh hang » anh hoang, anh hung, anh bang
cong tan » cong tac, cong san, cong ty
toan cau » toan cao, toan ban, toan tap
va dung » van dung, va duong, vat dung

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

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