Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
thanh toan » thanh hoa, thanh san, tinh toan
hieu tach » hieu cach, chiet tach, chieu sach
cua trong » cua truong, qua trong, ca trong
cua trung » cua truong, xuan trung, cua nhung
hach toan » manh toan
doc hieu » toc thieu, hoc thieu, hoc hien

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: doc hieu tach - hanh tranh ((cua trong) OR (cua trung)) cong ((hach toan) OR (thanh toan)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu tach - hanh tranh ((cua trong) OR (cua trung)) cong ((hach toan) or (thanh toan)) cau~".
• Adding a wildcard symbol may retrieve word variants: doc hieu tach - hanh tranh ((cua trong) OR (cua trung)) cong ((hach toan) or (thanh toan)) cau*.