Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cau treo » cau theo, cau tren, cau triet
vu nang » vuc nang, va nang, vu dang
van dau » van dao, phan dau
dau duc » dao duc, dang duc, dau nuoc
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
y nang » ky nang, ly nang, v nang
vi cau » va cau, ve cau, di cau

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 ((y nang) OR (vu nang)) ma hoa. hieu van dau duc va danh vi cau treo~.
• Adding a wildcard symbol may retrieve word variants: toc sach ((y nang) or (vu nang)) ma hoa. hieu van dau duc va danh vi cau treo*.