Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » thien van, lieu va
van hanh » van thanh, ban hanh, van anh
hieu va » lieu va, hieu qua
xuc van » duc van, luc van, vuc van
y nang » ky nang, ly nang, v nang
vi hoa » voi hoa, vi hoc, va hoa
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: toc sach y nang x hoi. ((((hieu van) OR (hieu ve))) or (hieu va)) cam xuc van hanh vi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang x hoi. ((((hieu van) OR (hieu ve))) OR (hieu va)) cam xuc van hanh vi hoa viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang x hoi. ((((hieu van) OR (hieu ve))) or (hieu va)) cam xuc van hanh vi hoa viet".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang x hoi. ((((hieu van) OR (hieu ve))) or (hieu va)) cam xuc van hanh vi hoa viet*.