Perhaps you should try some spelling variations:
thanh trung » thanh tung
quoc truong » quoc trong, hoc truong, quoc vuong
quoc trung » quoc hung, hoc trung, duc trung
theo chu » theo chieu, cho chu, chao chu
chu xanh » chu manh, chieu xanh, chua xang
ban toan » ban than, van toan, bao toan
bai toan » bai 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: theo chu xanh - thanh trung ((quoc truong) OR (quoc trung)) phuong ((ban toan) OR (bai toan)) cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo chu xanh - thanh trung ((quoc truong) OR (quoc trung)) phuong ((ban toan) or (bai toan)) cao~".
• Adding a wildcard symbol may retrieve word variants: theo chu xanh - thanh trung ((quoc truong) OR (quoc trung)) phuong ((ban toan) or (bai toan)) cao*.