Perhaps you should try some spelling variations:
ban hanh » ban hang
vien cac » vien bach, vien dai, gian cac
cua viet » ca viet, hoa viet, cua vat
mai hoi » mai khoi, dai hoi, lai hoi
sach ky » sac ky, sach y, sach ty
vien da » vien dai, hien dai
xuc ban » duc ban, cuc ban, quoc ban
tu sach » thu sach, su sach, te sach
ma hoi » xa hoi, ma hoa, me hoi
vi cua » vai cua, di cua

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 ((ma hoi) OR (mai hoi)). hieu ((vien cac) or (vien da)) xuc ban hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((ma hoi) OR (mai hoi)). hieu ((vien cac) OR (vien da)) xuc ban hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((ma hoi) OR (mai hoi)). hieu ((vien cac) or (vien da)) xuc ban hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((ma hoi) OR (mai hoi)). hieu ((vien cac) or (vien da)) xuc ban hanh vi cua viet*.