Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cao thuc » cao thuoc, bao thuc, can thuc
dua tren » dung tren
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
ky tang » ky nang, ky dang, kho tang
cuu tre » cua tre, cau tren, cau treo
va cao » va cac, va co, va dao
ma hoi » mai hoi, xa hoi, ma hoa
cua te » cua tu

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 ky tang ma hoi. hieu va cao thuc day hanh vi ((((dua tren) OR (cua te))) OR (cuu tre))~.
• Adding a wildcard symbol may retrieve word variants: thu sach ky tang ma hoi. hieu va cao thuc day hanh vi ((((dua tren) or (cua te))) or (cuu tre))*.