Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va
ban so » ban do, ban co, ban bo
so van » su van, vo van
vi cua » vai cua, di cua

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x ho. ((hieu va) OR (hieu qua)) ban so van hanh vi cua viet~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x ho. ((hieu va) OR (hieu qua)) ban so van hanh vi cua viet*.