Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
toc sach » hoc sach, doc sach, thuoc sach
hai cuc » hai cua, thai cua, hai huoc
dua ban » dia ban, cua ban, qua ban
cam dua » ca dua, cay dua, chay dua
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
dai hoi » dai hoc, dai hai, dai moi
mai hoi » mai khoi, lai hoi, mai doi
ty nang » ky nang, ty xang, ty hang
va cam » va cham, va cac, va cao

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