Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
tu sach » thu sach, su sach, te sach
duc ban » duc tan, duc van, dua ban
hoi cua » hoi chuc
hoi cuu » hoi chu, ho cuu, hoi cau
ve pham » vi pham, v pham, ve phan
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi

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 hoc)). hieu ve pham duc ban thanh ((hoi cuu) or (hoi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((mai hoi) OR (dai hoc)). hieu ve pham duc ban thanh ((hoi cuu) OR (hoi cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((mai hoi) or (dai hoc)). hieu ve pham duc ban thanh ((hoi cuu) or (hoi cua)) tre*.