Perhaps you should try some spelling variations:
thanh hoi » thanh hoai, thanh hoa, thanh hai
tu sach » thu sach, su sach, te sach
hoi cuu » hoi chu, hoi cua, ho cuu
dua ban » cua ban, qua ban, mua ban
vu cham » va cham, vu kham, tu cham
sach ky » sac ky, sach y, sach ty
hieu vu » hieu va, hieu ve, hieu su
dai hoi » dai hoc, dai hai, dai moi
mai hoi » mai khoi, lai hoi, mai doi
cuu tre » cua tre, cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ((mai hoi) or (dai hoi)). hieu vu cham ((dua ban) OR (dia ban)) thanh hoi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((mai hoi) OR (dai hoi)). hieu vu cham ((dua ban) OR (dia ban)) thanh hoi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((mai hoi) or (dai hoi)). hieu vu cham ((dua ban) OR (dia ban)) thanh hoi cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((mai hoi) or (dai hoi)). hieu vu cham ((dua ban) OR (dia ban)) thanh hoi cuu tre*.