Perhaps you should try some spelling variations:
ban benh » san benh, ba benh, ban banh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
bo benh » so benh, o benh, ba benh
cua tre » cua te, cuu tre, cua triet

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: tu sach ty nang x ho. hieu va pham duc ((ban benh) OR (bo benh)) dai cua tre~.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x ho. hieu va pham duc ((ban benh) or (bo benh)) dai cua tre*.