Perhaps you should try some spelling variations:
ban hang » ngan hang
van hanh » van thanh, ban hanh, van anh
cua viet » ca viet, hoa viet, cua vat
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
va cam » va cham, va cac, va cao
vi cua » vai cua, di cua
5 hoi » o hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang ((5 hoi) or (x ho)). hieu va cam xuc ((ban hang) or (van hanh)) vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ((5 hoi) OR (x ho)). hieu va cam xuc ((ban hang) OR (van hanh)) vi cua viet.
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ((5 hoi) or (x ho)). hieu va cam xuc ((ban hang) or (van hanh)) vi cua viet*.