Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, vu khach
su sach » so sach
van cac » van hac, van cau, van bac
cac toc » cac toi, cac nuoc, cac thoi
va hanh » van hanh, va thanh, va danh
cua tre » cuu tre, cua triet, dua tren
toc va » hoc va, toc ta, tuc va
cua te » cua tu
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: ((vu sach) OR (su sach)) ky nang x hoi. hieu van cac toc va hanh vi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (su sach)) ky nang x hoi. hieu van cac toc va hanh vi ((cua tre) OR (cua te))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) OR (su sach)) ky nang x hoi. hieu van cac toc va hanh vi ((cua tre) or (cua te))*".