Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
hoc sach » hoc sinh, hoc cac, hoc anh
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
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 (hoc sach)) ky lang xa hoi. hieu van nam thuc ((va dao) or (va dau)) vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ky lang xa hoi. hieu van nam thuc ((va dao) OR (va dau)) vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (hoc sach)) ky lang xa hoi. hieu van nam thuc ((va dao) or (va dau)) vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (hoc sach)) ky lang xa hoi. hieu van nam thuc ((va dao) or (va dau)) vai cuu tre*.