Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cam truc » cau truc, nam truc, lam truoc
su sach » so sach, vu sach
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
qua cam » qua cham, qua cac, qua ca
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua
co hoi » co hoc, co loi
o hoi » o hoc, o hai, o hoa

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 ((o hoi) OR (co hoi)). hieu qua cam truc va hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (toc sach)) ky nang ((o hoi) OR (co hoi)). hieu qua cam truc va hanh va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (toc sach)) ky nang ((o hoi) OR (co hoi)). hieu qua cam truc va hanh va cua tre*".