Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
van hanh » van thanh, ban hanh, van anh
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
cam luc » cam xuc, cau luc
va hanh » va thanh, va danh, ban hanh
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang x hoi. ((hieu van) or (hieu va)) cam luc ((va hanh) OR (van hanh)) tu va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x hoi. ((hieu van) OR (hieu va)) cam luc ((va hanh) OR (van hanh)) tu va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x hoi. ((hieu van) or (hieu va)) cam luc ((va hanh) OR (van hanh)) tu va triet".
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. ((hieu van) or (hieu va)) cam luc ((va hanh) OR (van hanh)) tu va triet*.