Perhaps you should try some spelling variations:
mai khoi » mai khoa, tai khoa, dai khoa
cac khoi » cac thoi, cac khoan, cach thoi
tu sach » thu sach, su sach, te sach
nam mua » nam cua, nam qua, nam luat
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
nam xua » nam cua, nam qua, nam luat
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
vi cua » vai cua, di cua

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 y nang ((mai khoi) OR (cac khoi)). lieu va ((nam xua) OR (nam mua)) va danh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((mai khoi) OR (cac khoi)). lieu va ((nam xua) or (nam mua)) va danh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((mai khoi) OR (cac khoi)). lieu va ((nam xua) or (nam mua)) va danh vi cua tre*.