Perhaps you should try some spelling variations:
cham quoc » chuan quoc, cham soc, cua quoc
toc sach » hoc sach, doc sach, thuoc sach
hanh dai » hanh tai, hanh dao, vanh dai
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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)) y nang x hoi. hieu ve ((cham quoc) OR (han quoc)) va hanh dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y nang x hoi. hieu ve ((cham quoc) or (han quoc)) va hanh dai cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y nang x hoi. hieu ve ((cham quoc) or (han quoc)) va hanh dai cua tre*.