Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
toc sach » hoc sach, doc sach, thuoc sach
dua ban » dia ban, cua ban, qua ban
hai cua » thai cua, dai cua, hoi cua
hai cuc » tai cuc, thai cua, hai huoc
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ty nang » ky nang, ty hang, ly nang
ca dua » cay dua, ca cua, ca da
ve ca » ve cac, ve cai, ve cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((ty nang) or (ty xang)) mai hoi. hieu ve ca dua ban thanh ((hai cuc) OR (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty nang) OR (ty xang)) mai hoi. hieu ve ca dua ban thanh ((hai cuc) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty nang) or (ty xang)) mai hoi. hieu ve ca dua ban thanh ((hai cuc) OR (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty nang) or (ty xang)) mai hoi. hieu ve ca dua ban thanh ((hai cuc) OR (hai cua)) tre*.