Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, hieu lang
hieu quang » thieu quang, hieu quan, hieu qua
hanh tang » hanh trang, anh tang, hanh mang
vat dung » van dung, viet dung, mat duong
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan cau » toan cao, toan ban, toan tap
va dung » van dung, va duong, va ung

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: ho ((chieu sang) OR (hieu quang)) - hanh tang ((va dung) OR (vat dung)) cong san toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sang) or (hieu quang)) - hanh tang ((va dung) OR (vat dung)) cong san toan cau~".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) or (hieu quang)) - hanh tang ((va dung) OR (vat dung)) cong san toan cau*.