Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu qua, diep quang
chat nhung » chat ngung, thuat nhung, cua nhung
hieu quan » hieu qua, lieu quan, thien quan
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
toan cau » toan cao, toan ban, toan tap

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: nhu ((hieu quang) OR (hieu quan)) - hanh tinh chat nhung ((cong dan) OR (cong san)) toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "nhu ((hieu quang) OR (hieu quan)) - hanh tinh chat nhung ((cong dan) or (cong san)) toan cau~".
• Adding a wildcard symbol may retrieve word variants: nhu ((hieu quang) OR (hieu quan)) - hanh tinh chat nhung ((cong dan) or (cong san)) toan cau*.