Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
ky tang » ky nang, ky dang, kho tang
ky lang » ky nang, ky dang, tay lang
hieu ca » hieu cac, hieu cua, hieu va
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
ca nam » cua nam, cai nam, ha nam
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.

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky lang) OR (ky tang)) xa hoi. hieu ca nam thuc ((va dan) OR (va dao)) vai cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ky lang) or (ky tang)) xa hoi. hieu ca nam thuc ((va dan) OR (va dao)) vai cuu tre~".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ky lang) or (ky tang)) xa hoi. hieu ca nam thuc ((va dan) OR (va dao)) vai cuu tre*.