Perhaps you should try some spelling variations:
thai doan » chan doan, tap doan, giai doan
thai dua » thai cua, thi dua, thai luan
ban hanh » ban hang
sach ky » sac ky, sach y, sach ty
xuc ban » duc ban, cuc ban, quoc ban
tu sach » thu sach, su sach, te sach
cac xuc » cam xuc, cac nuoc, chat xuc
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
co hai » co dai, co hoi, o hai
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: tu sach ky nang ((o hoi) or (co hai)). hieu ve cac xuc ban hanh ((thai dua) or (thai doan)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hoi) OR (co hai)). hieu ve cac xuc ban hanh ((thai dua) OR (thai doan)) tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hoi) or (co hai)). hieu ve cac xuc ban hanh ((thai dua) or (thai doan)) tren*.