Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thu sach » tu sach, thuat sach, thuoc sach
ve cham » va cham, ve chat, vu cham
duc ban » duc tan, duc van, dua ban
sach ky » sac ky, sach y, sach ty
ve cac » va cac, vien cac
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang o hoi. hieu ((ve cac) or (ve cham)) duc ban thanh ((hoi cua) OR (hoi chuc)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang o hoi. hieu ((ve cac) OR (ve cham)) duc ban thanh ((hoi cua) OR (hoi chuc)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang o hoi. hieu ((ve cac) or (ve cham)) duc ban thanh ((hoi cua) OR (hoi chuc)) te".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang o hoi. hieu ((ve cac) or (ve cham)) duc ban thanh ((hoi cua) OR (hoi chuc)) te*.