Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
cao thuc » cao thuoc, bao thuc, can thuc
cau treo » cau theo, cau tren, cau triet
doc sach » hoc sach, nuoc sach, dac sac
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
cuu tre » cua tre, cau tren
v nang » va nang, vu nang, van nang
va dan » ca dan, va dao, va dau
dan di » danh di, dan da, dan de
va cao » va cac, va co, va 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 (doc sach)) v nang xa hoi. hieu va cao thuc va dan di ((cuu tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) v nang xa hoi. hieu va cao thuc va dan di ((cuu tre) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) v nang xa hoi. hieu va cao thuc va dan di ((cuu tre) or (cau treo))*.