Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
thuc va » thuc vat, thuc dan, thuc day
van cau » van dau, van hau, van chat
lang xa » lang ha, dang xay, lang van
sach tu » sach thu, cach tu, sach ty
sac ky » cac ky, sai ky
xac va » tac va, ac va, bac va
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 ((sac ky) or (sach tu)) lang xa hoi. hieu van cau ((xac va) or (thuc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sac ky) OR (sach tu)) lang xa hoi. hieu van cau ((xac va) OR (thuc va)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: so ((sac ky) or (sach tu)) lang xa hoi. hieu van cau ((xac va) or (thuc va)) hanh vi cua tre*.