Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
truc va » thuc va, thuc vat, trung va
sach ky » sac ky, sach y, sach ty
van hac » van hoc, van ha, van hai
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, tuc xa, duc va
vi cua » vai cua, di cua

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: su sach ky ((nang xa) OR (lang xa)) hoi. hieu van hac ((tuc va) OR (truc va)) hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (lang xa)) hoi. hieu van hac ((tuc va) OR (truc va)) hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (lang xa)) hoi. hieu van hac ((tuc va) OR (truc va)) hanh vi cua tre*.