Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va thanh » ban thanh, va tinh, le thanh
cac duc » cac du, cao duc, cac dac
day cua » dai cua
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
ma hoi » mai hoi, xa hoi, ma hoa

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)) ky nang ma hoi. hieu ve cac duc ((va thanh) OR (gia thanh)) day cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky nang ma hoi. hieu ve cac duc ((va thanh) or (gia thanh)) day cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky nang ma hoi. hieu ve cac duc ((va thanh) or (gia thanh)) day cua tre*.