Perhaps you should try some spelling variations:
ban hanh » ban hang
so sach » so sanh, bo sach, co sach
ty nang » ky nang, ty xang, ty hang
hanh ca » hanh cac, hanh cat, hanh cua
duc ban » duc tan, duc van, dua ban
sach ty » sach y, sach tu, sach thu
va cao » va cac, va co, va dao
ca cua » co cua
ve cam » ve cham, ve cac, va cam
cua te » cua tu
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, o hoa

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 ty nang ((o hoi) OR (o hai)). hieu ((ve cam) or (va cao)) duc ban hanh ca cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty nang ((o hoi) OR (o hai)). hieu ((ve cam) OR (va cao)) duc ban hanh ca cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty nang ((o hoi) OR (o hai)). hieu ((ve cam) or (va cao)) duc ban hanh ca cua te".
• Adding a wildcard symbol may retrieve word variants: so sach ty nang ((o hoi) OR (o hai)). hieu ((ve cam) or (va cao)) duc ban hanh ca cua te*.