Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, thuc vat
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
van cau » van dau, van hau, van chat
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ty nang ma hoi. hieu van cau ((thuc dan) OR (hoc dan)) thanh tai cua tre~".
• Adding a wildcard symbol may retrieve word variants: hoc sach ty nang ma hoi. hieu van cau ((thuc dan) OR (hoc dan)) thanh tai cua tre*.