Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh hoi » thanh hoai, thanh hoa, thanh hai
cham cua » chat cua, cham cuu, ham cua
tu sach » thu sach, su sach, te sach
cuu tre » cau tren, cau treo
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
sach ky » sac ky, sach y, sach ty
dai moi » doi moi, dai hoi
mai hoi » mai khoi, dai hoi, lai hoi
cua tre » cua te, cua triet, dua tren

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 nang ((mai hoi) OR (dai moi)). hieu ve cham cua ban thanh hoi ((cuu tre) OR (cua tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((mai hoi) or (dai moi)). hieu ve cham cua ban thanh hoi ((cuu tre) OR (cua tre))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((mai hoi) or (dai moi)). hieu ve cham cua ban thanh hoi ((cuu tre) OR (cua tre))*.