Perhaps you should try some spelling variations:
thien van » thi van
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
duc ban » duc tan, duc van, duc man
vai cua » dai cua, hai cua, lai cua
dua ban » dia ban, cua ban, qua ban
sach vu » sach va, sach tu, sach uu
nang xa » nang x, lang xa, nang ma
vu nang » vuc nang, va nang, vu dang
cua tre » cua te, cuu tre, cua triet

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 vu nang xa hoi. ((hieu van) OR (thien van)) lam ((duc ban) OR (dua ban)) hanh vai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang xa hoi. ((hieu van) or (thien van)) lam ((duc ban) OR (dua ban)) hanh vai cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang xa hoi. ((hieu van) or (thien van)) lam ((duc ban) OR (dua ban)) hanh vai cua tre*.