Perhaps you should try some spelling variations:
ban hang » ngan hang
sach ky » sac ky, sach y, sach ty
via cua » gia cua, gian cua, giau cua
cham so » cham soc, cham o, ham so
su sach » so sach, vu sach
hieu vu » hieu va, hieu ve, hieu su
lang ha » long ha
ky lang » ky nang, ky dang, ky tang
ha hoi » hoa hoi, ha noi, xa hoi
so ban » sao ban, so bang, co ban
va cua » va chua, ca cua, ma cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky lang ha hoi. ((hieu vu) or (hieu qua)) cham so ban hang ((va cua) or (via cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky lang ha hoi. ((hieu vu) OR (hieu qua)) cham so ban hang ((va cua) OR (via cua)) triet.
• Adding a wildcard symbol may retrieve word variants: su sach ky lang ha hoi. ((hieu vu) or (hieu qua)) cham so ban hang ((va cua) or (via cua)) triet*.