Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
thanh vi » thanh va, thanh ve, nhanh vi
ve triet » va trien, su triet
hieu va » lieu va, hieu qua
sach vu » sach va, sach tu, sach uu
hau xuc » chat xuc
vu nang » vuc nang, va nang, vu dang
xuc va » duc va, tuc va, luc va
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach vu nang o hoi. ((hieu van) OR (hieu va)) hau xuc va ((thanh vi) OR (hanh vi)) ve triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach vu nang o hoi. ((hieu van) OR (hieu va)) hau xuc va ((thanh vi) or (hanh vi)) ve triet~".
• Adding a wildcard symbol may retrieve word variants: thu sach vu nang o hoi. ((hieu van) OR (hieu va)) hau xuc va ((thanh vi) or (hanh vi)) ve triet*.