Perhaps you should try some spelling variations:
van sach » ban sach, van hach, ngan sach
hanh lai » hanh lam, hanh tai, thanh lap
tu sach » thu sach, su sach, te sach
va sach » va cach, a sach, vu sach
va hanh » van hanh, va thanh, va danh
lai cuu » lai cua, lai chau, lai cuoc
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, 5 hoi

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 ((x hoi) OR (x ho)). hieu ((va sach) OR (van sach)) nuoc va hanh lai cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((x hoi) or (x ho)). hieu ((va sach) OR (van sach)) nuoc va hanh lai cuu tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x hoi) or (x ho)). hieu ((va sach) OR (van sach)) nuoc va hanh lai cuu tre*.