Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
y nang » ky nang, ly nang, v nang
xac va » tac va, ac va, bac va
tuc va » thuc va, truc va, tuc xa
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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: tu sach y nang x hoi. ((hieu van) OR (hieu va)) cam ((xac va) OR (tuc va)) hanh vi cua vat~.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang x hoi. ((hieu van) or (hieu va)) cam ((xac va) or (tuc va)) hanh vi cua vat*.