Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach ty, sach kem
cua tre » cua te, cuu tre, cua triet
lang ha » long ha
ha hoi » hoa hoi, ha noi, xa hoi
tac va » tac da, tac xa, tac ha
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 ky) or (sach y)) lang ha hoi. hieu van dao ((tac va) or (tuc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach ky) OR (sach y)) lang ha hoi. hieu van dao ((tac va) OR (tuc va)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: so ((sach ky) or (sach y)) lang ha hoi. hieu van dao ((tac va) or (tuc va)) hanh vi cua tre*.