Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
hieu va » hieu qua
lang ha » long ha
sach o » sach lo, sac o, sach y
ha hoi » hoa hoi, ha noi, xa hoi
va dan » ca dan, va dau, va dap
va dao » ca dao
o lang » hoa lang, hoi lang

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 o lang ha hoi. ((hieu va) or (lieu va)) nam thuc ((va dan) or (va dao)) vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach o lang ha hoi. ((hieu va) OR (lieu va)) nam thuc ((va dan) OR (va dao)) vai cuu tre.
• Adding a wildcard symbol may retrieve word variants: toc sach o lang ha hoi. ((hieu va) or (lieu va)) nam thuc ((va dan) or (va dao)) vai cuu tre*.