Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
nam thuc » nam thuoc, am thuc, nam thu
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
va nam » van nam, ha nam, va nay
va dan » ca dan, va dau, va dap
va dao » ca dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (thuoc sach)) ky nang xa hoi. hieu va nam thuc ((va dan) OR (va dao)) hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) ky nang xa hoi. hieu va nam thuc ((va dan) OR (va dao)) hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (thuoc sach)) ky nang xa hoi. hieu va nam thuc ((va dan) OR (va dao)) hai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (thuoc sach)) ky nang xa hoi. hieu va nam thuc ((va dan) OR (va dao)) hai cua tre*.