Perhaps you should try some spelling variations:
sach kem » hanh kem
hieu van » hieu va, thien van, lieu va
dau thuc » dan thuc, dai thuc, dam thuc
vat xanh » vat thanh, sat anh, dat anh
xanh dai » vanh dai, xanh di, xanh tai
cua viet » ca viet, hoa viet, cua vat
sach ty » sach y, sach tu, sach thu
van dau » van dao, phan dau
x hoi » xa hoi, o hoi, x ho

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: thu ((sach kem) OR (sach ty)) nang x hoi. hieu van dau thuc vat xanh dai cua viet~.
• Adding a wildcard symbol may retrieve word variants: thu ((sach kem) or (sach ty)) nang x hoi. hieu van dau thuc vat xanh dai cua viet*.