Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu ve » hieu va, hieu van
hai cua » thai cua, hoi cua, lai cua
duc ban » duc tan, duc van, dua ban
ve pham » vi pham, v pham, ve phan
mai hoi » mai khoi, dai hoi, lai hoi
ky tang » ky nang, ky dang, kho tang
sac ky » cac ky, sai ky
ma hoi » xa hoi, ma hoa, me hoi
su sac » su sach, su cac, su xac

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: su sac ky tang ((ma hoi) OR (mai hoi)). hieu ve pham duc ban thanh ((hai cua) OR (dai cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky tang ((ma hoi) OR (mai hoi)). hieu ve pham duc ban thanh ((hai cua) or (dai cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: su sac ky tang ((ma hoi) OR (mai hoi)). hieu ve pham duc ban thanh ((hai cua) or (dai cua)) tre*.