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

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