Perhaps you should try some spelling variations:
thanh trung » thanh tung
manh trung » manh tung, manh hung, sinh trung
trong vinh » trong kinh, trong sinh, trong linh
bien tinh » bi tinh, yen tinh, diep tinh
cong vinh » cong trinh, cong viec, cong viet
va thong » va thuong, va phuong, he thong
toan tap » toan ban
so bien » mot bien

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: so bien tinh - ((thanh trung) OR (manh trung)) va thong ((cong vinh) OR (trong vinh)) toan tap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so bien tinh - ((thanh trung) or (manh trung)) va thong ((cong vinh) OR (trong vinh)) toan tap~".
• Adding a wildcard symbol may retrieve word variants: so bien tinh - ((thanh trung) or (manh trung)) va thong ((cong vinh) OR (trong vinh)) toan tap*.