Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
chau tre » chay tren, chau tho, cho tre
lang xa » lang ha, dang xay, lang van
hieu va » hieu qua
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
ca dan » cac dan, ca dao
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 ky lang xa hoi. ((hieu va) or (lieu va)) nam thuc ((ca dan) or (va dao)) lai chau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. ((hieu va) OR (lieu va)) nam thuc ((ca dan) OR (va dao)) lai chau tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. ((hieu va) or (lieu va)) nam thuc ((ca dan) or (va dao)) lai chau tre*.