Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
nang mai » nang ma, nang tai, lang mai
cam dua » ca dua, cay dua, chay dua
hai cua » thai cua, dai cua, hoi cua
hai cuc » tai cuc, thai cua, hai huoc
dua ban » dia ban, cua ban, qua ban
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
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) or (doc sach)) ty nang mai hoi. hieu va cam dua ban thanh ((hai cuc) OR (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ty nang mai hoi. hieu va cam dua ban thanh ((hai cuc) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ty nang mai hoi. hieu va cam dua ban thanh ((hai cuc) OR (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ty nang mai hoi. hieu va cam dua ban thanh ((hai cuc) OR (hai cua)) tre*.