Perhaps you should try some spelling variations:
trung cong » truong cong, trong cong, trung uong
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
cua trung » cua truong, xuan trung, cua nhung
manh toan » thanh toan, anh tuan, tinh toan
ho thiet » hoc thiet, hoa thiet, hoc thieu
so thiet » soc thiet, hoc thiet, hoa thiet
tinh cua » trinh cua, sinh cua, tinh chat
dan toan » van toan, dan than, xuan toan

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 thiet) OR (so thiet)) tach - hanh tinh cua trung cong ((manh toan) OR (dan toan)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho thiet) OR (so thiet)) tach - hanh tinh cua trung cong ((manh toan) or (dan toan)) cau~".
• Adding a wildcard symbol may retrieve word variants: ((ho thiet) OR (so thiet)) tach - hanh tinh cua trung cong ((manh toan) or (dan toan)) cau*.