Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cam thuc » am thuc, nam thuc, cam thu
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
hieu va » lieu va, hieu qua
va danh » va dinh, va dan, va hanh
cuu tre » cua tre, cau tren, cau treo
va cam » va cham, va cac, va cao
di cuu » di cau, di cua, dinh cuu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ty xang xa hoi. hieu va cam thuc ((va danh) or (van hanh)) di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty xang xa hoi. hieu va cam thuc ((va danh) OR (van hanh)) di cuu tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ty xang xa hoi. hieu va cam thuc ((va danh) or (van hanh)) di cuu tre*.