Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
hieu van » hieu va, thien van, lieu va
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
co sach » bo sach, cuon sach, hoc sach
van cac » van hac, van cau, van bac
cac toc » cac toi, cac nuoc, cac thoi
ta hanh » ta thanh, va hanh, tu hanh
hanh di » hanh vi, hanh de, hang di
toc ta » toc tay, toc thai

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 ho. hieu van cac toc ta 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 ho. hieu van cac toc ta 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 ho. hieu van cac toc ta hanh di ((cua triet) OR (va triet))".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (co sach)) ky nang x ho. hieu van cac toc ta hanh di ((cua triet) OR (va triet))*.