Perhaps you should try some spelling variations:
va thanh » ban thanh, va tinh, le thanh
te sach » toc sach
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
day cua » dai cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, me hoi
ve cac » va cac, vien cac

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 y nang ((ma hoi) OR (ma hoa)). 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 y nang ((ma hoi) OR (ma hoa)). hieu ve cac duc ((va thanh) or (gia thanh)) day cua tre~".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ((ma hoi) OR (ma hoa)). hieu ve cac duc ((va thanh) or (gia thanh)) day cua tre*.