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