Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
ban thanh » ban hanh, ban hang
tu sach » thu sach, su sach, te sach
cam dua » ca dua, chay dua, cach dua
vai cua » dai cua, hai cua, lai cua
cay dua » chay dua, cay lua, ca dua
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ma hoi » xa hoi, ma hoa, me hoi

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 nang ((ma hoi) OR (mai hoi)). hieu ve ((cam dua) or (cay dua)) ban thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((ma hoi) OR (mai hoi)). hieu ve ((cam dua) OR (cay dua)) ban thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((ma hoi) OR (mai hoi)). hieu ve ((cam dua) or (cay dua)) ban thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((ma hoi) OR (mai hoi)). hieu ve ((cam dua) or (cay dua)) ban thanh vai cua tre*.