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
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
y nang » ky nang, ly nang, v nang
van am » van nam, van lam, van dam
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 y nang ((x hoi) or (xa hoi)). hieu van am thuc ((va danh) or (va hanh)) mai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((x hoi) OR (xa hoi)). hieu van am thuc ((va danh) OR (va hanh)) mai va triet.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x hoi) or (xa hoi)). hieu van am thuc ((va danh) or (va hanh)) mai va triet*.