Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cham tuc » nham thuc, pham thuc, tham thuc
hanh di » hanh de, hang di, danh di
tuc van » thuc van, truc van, tuc va
va cham » va chat, va tham
hieu va » lieu va, hieu qua
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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: ((te sach) OR (toc sach)) ty nang x hoi. hieu va cham tuc van ((hanh di) OR (hanh vi)) cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ty nang x hoi. hieu va cham tuc van ((hanh di) OR (hanh vi)) cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ty nang x hoi. hieu va cham tuc van ((hanh di) OR (hanh vi)) cua tre*.