Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
mau hoa » cau hoa, mai hoa, mau ho
ky danh » ky anh, ky dang
va nam » van nam, ha nam, va nay

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 ky danh ((mau hoa) OR (ma hoa)). lieu va nam thuc ((van hanh) OR (ban hanh)) tai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky danh ((mau hoa) OR (ma hoa)). lieu va nam thuc ((van hanh) or (ban hanh)) tai cua tre~".
• Adding a wildcard symbol may retrieve word variants: toc sach ky danh ((mau hoa) OR (ma hoa)). lieu va nam thuc ((van hanh) or (ban hanh)) tai cua tre*.