Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
ban thanh » ban hanh, ban hang
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
van cua » vang cua, ban cua, dan cua
dua ban » dia ban, cua ban, qua ban
cua tre » cua te, cuu tre, cua triet
dai hoa » dai khoa, dai hoc, dai hoi
mai hoa » mai khoa, ma hoa, lai hoa
ky dang » ky nang, ky danh
va cai » va cac, va bai, va dai
va ca » va cac, va cao, va cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky dang ((mai hoa) or (dai hoa)). hieu ((va ca) OR (va cai)) dua ban thanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ((mai hoa) OR (dai hoa)). hieu ((va ca) OR (va cai)) dua ban thanh van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ((mai hoa) or (dai hoa)). hieu ((va ca) OR (va cai)) dua ban thanh van cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((mai hoa) or (dai hoa)). hieu ((va ca) OR (va cai)) dua ban thanh van cua tre*.