Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
so sach » bo sach, co sach, hoc sach
van lam » van nam
dang xa » dang xay, lang xa, dang ha
ty dang » ty xang, ky dang, ty hang
so sanh » do sanh
cua tre » cua te, cuu tre, cua triet
xac va » tac va, ac va, bac va
tuc va » thuc va, truc va, tuc xa
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) OR (so sanh)) ty dang xa hoi. hieu van lam ((xac va) or (tuc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) ty dang xa hoi. hieu van lam ((xac va) OR (tuc va)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) OR (so sanh)) ty dang xa hoi. hieu van lam ((xac va) or (tuc va)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((so sach) OR (so sanh)) ty dang xa hoi. hieu van lam ((xac va) or (tuc va)) hanh vi cua tre*.