Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dau thuc » dan thuc, dai thuc, dam thuc
vat hanh » vat thanh, van hanh, va hanh
hanh lam » thanh lap, hanh kem, hanh va
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
su viet » so viet
y nang » ly nang, v nang, may nang
va dau » 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 ((y nang) or (ky nang)) ma hoa. hieu va dau thuc vat hanh lam ((cuu tre) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((y nang) OR (ky nang)) ma hoa. hieu va dau thuc vat hanh lam ((cuu tre) OR (su viet)).
• Adding a wildcard symbol may retrieve word variants: toc sach ((y nang) or (ky nang)) ma hoa. hieu va dau thuc vat hanh lam ((cuu tre) or (su viet))*.