Perhaps you should try some spelling variations:
ban hanh » ban hang
so sach » so sanh, bo sach, co sach
hieu va » lieu va, hieu qua
y nang » ky nang, ly nang, v nang
va cam » va cham, va cac, va cao
cam tu » cam thu, nam tu, dam tu
tu ban » thu ban, te ban
di cua » dai cua, doi cua, do cua
de cua » le cua, te cua, dieu cua
x hoi » xa hoi, o hoi, x ho

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: "so sach y nang x hoi. hieu va cam tu ban hanh ((di cua) OR (de cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: so sach y nang x hoi. hieu va cam tu ban hanh ((di cua) OR (de cua)) tre*.