Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
co sach » bo sach, cuon sach, hoc sach
hieu ve » hieu va, hieu van
cac toc » cac toi, cac nuoc, cac thoi
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
su sach » so sach, vu sach
ve cac » va cac, vien cac
toc va » hoc va, toc ta, tuc va
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (co sach)) ky nang ((x hoi) OR (o hoi)). hieu ve cac toc va hanh di cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (co sach)) ky nang ((x hoi) OR (o hoi)). hieu ve cac toc va hanh di cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (co sach)) ky nang ((x hoi) OR (o hoi)). hieu ve cac toc va hanh di cua triet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (co sach)) ky nang ((x hoi) OR (o hoi)). hieu ve cac toc va hanh di cua triet*.