Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thu sach » tu sach, thuat sach, thuoc sach
cua viet » ca viet, hoa viet, cua vat
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ve bao » te bao, va bao
bao bo » bac bo, ban bo, nao bo
bo van » vo van, so van, do van
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: thu sach ky nang ((5 hoi) or (x ho)). hieu ve bao bo van hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((5 hoi) OR (x ho)). hieu ve bao bo van hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((5 hoi) or (x ho)). hieu ve bao bo van hanh vi cua viet*.