Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
hieu ve » hieu va
va hanh » van hanh, va thanh, va danh
vai hoa » va hoa, dai hoa, lai hoa
y nang » ky nang, ly nang, v nang
cam tu » cam thu, nam tu, dam tu
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 ve) or (hieu van)) cam tu va hanh ((vai hoa) OR (van hoa)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x hoi. ((hieu ve) OR (hieu van)) cam tu va hanh ((vai hoa) OR (van hoa)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x hoi. ((hieu ve) or (hieu van)) cam tu va hanh ((vai hoa) OR (van hoa)) viet".
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. ((hieu ve) or (hieu van)) cam tu va hanh ((vai hoa) OR (van hoa)) viet*.