Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
via cua » gia cua, gian cua, giau cua
y nang » ky nang, ly nang, v nang
va cam » va cham, va cac, va cao
cam so » nam so, ham so, cam lo
va cua » va chua, ca cua, ma cua
so va » so van, so vat, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y nang ((xa hoi) or (ma hoa)). hieu va cam so va hanh ((va cua) or (via cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang ((xa hoi) OR (ma hoa)). hieu va cam so va hanh ((va cua) OR (via cua)) tre.
• Adding a wildcard symbol may retrieve word variants: thu sach y nang ((xa hoi) or (ma hoa)). hieu va cam so va hanh ((va cua) or (via cua)) tre*.