Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hanh dai » hanh tai, hanh dao, vanh dai
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
cam thuc » am thuc, nam thuc, cam thu
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
va cam » va cham, va cac, va cao
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.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (su sach)) ky nang ((o hoi) OR (co hoi)). hieu va cam thuc dan hanh dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (su sach)) ky nang ((o hoi) OR (co hoi)). hieu va cam thuc dan hanh dai cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (su sach)) ky nang ((o hoi) OR (co hoi)). hieu va cam thuc dan hanh dai cua tre*.