Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
vai cua » dai cua, hai cua, lai cua
va dan » ca dan, va dao, va dap
va dau » va dao
x hoi » xa hoi, o hoi, 5 hoi
ve am » va am

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: tu sach ky nang ((x hoi) OR (x ho)). hieu ve am thuc ((va dan) OR (va dau)) vai cua triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((x hoi) or (x ho)). hieu ve am thuc ((va dan) OR (va dau)) vai cua triet~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) or (x ho)). hieu ve am thuc ((va dan) OR (va dau)) vai cua triet*.