Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang mai » nang ma, nang tai, lang mai
sach ty » sach y, sach tu, sach thu
hai cua » thai cua, dai cua, hoi cua
hai cuc » tai cuc, thai cua, hai huoc
qua ban » cua ban, qua quan
dua ban » dia ban, cua ban, mua ban
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ty nang » ky nang, ty xang, ty hang
ve cam » ve cham, ve cac, va cam

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. hieu ve cam ((dua ban) OR (qua 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 mai hoi. hieu ve cam ((dua ban) OR (qua 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 mai hoi. hieu ve cam ((dua ban) OR (qua ban)) thanh ((hai cuc) or (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang mai hoi. hieu ve cam ((dua ban) OR (qua ban)) thanh ((hai cuc) or (hai cua)) tre*.