Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
hanh vai » hanh vi, hanh va, hanh tai
su sach » so sach, vu sach
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
ve nam » he nam, va nam, le nam

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 lang xa hoi. hieu ve nam thuc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (toc sach)) ky lang xa hoi. hieu ve nam thuc va hanh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (toc sach)) ky lang xa hoi. hieu ve nam thuc va hanh vai cua tre*.