Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
ky dang » ky nang, ky danh
ky tang » ky nang, kho tang, ky trong
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao

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 ((ky tang) OR (ky dang)) xa hoi. hieu va cam thuc ((va hanh) OR (va danh)) vai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky tang) or (ky dang)) xa hoi. hieu va cam thuc ((va hanh) OR (va danh)) vai cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky tang) or (ky dang)) xa hoi. hieu va cam thuc ((va hanh) OR (va danh)) vai cua tre*.