Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu quang » thieu quang, hieu quan, hieu qua
hieu lang » chieu sang, nhieu tang, hieu van
nam thang » nam thanh, nam trong, nam trung
tam hang » pham hang, tam huong, thai hang
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
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: ho ((hieu lang) OR (hieu quang)) - thanh trung ((tam hang) OR (nam thang)) cong dan toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu lang) OR (hieu quang)) - thanh trung ((tam hang) or (nam thang)) cong dan toan cau~".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu lang) OR (hieu quang)) - thanh trung ((tam hang) or (nam thang)) cong dan toan cau*.