Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
chat duc » chat xuc, chat doc, chet duoc
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (toc sach)) ky nang ((x hoi) OR (o hoi)). hieu ve chat duc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (toc sach)) ky nang ((x hoi) OR (o hoi)). hieu ve chat duc va hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (toc sach)) ky nang ((x hoi) OR (o hoi)). hieu ve chat duc va hanh vi cua tre*".