Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va triet » va thiet, va trien, ve triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
van am » van nam, van lam, van dam
va dan » ca dan, va dao, va dau
x hoi » o hoi, x ho, 5 hoi

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 ((x hoi) or (xa hoi)). hieu van am thuc ((va dan) or (va hanh)) mai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((x hoi) OR (xa hoi)). hieu van am thuc ((va dan) OR (va hanh)) mai va triet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) or (xa hoi)). hieu van am thuc ((va dan) or (va hanh)) mai va triet*.