Perhaps you should try some spelling variations:
trong van » trong cac
te sach » toc sach
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
toc va » hoc va, tuc va, loc va
toc ta » toc tay, toc thai
vi cua » vai cua, di cua
va hac » van hac, va khac, va cac

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: te sach y ((nang x) OR (trong van)) hoi. hieu va hac ((toc va) OR (toc ta)) hanh vi cua tre~.
• Adding a wildcard symbol may retrieve word variants: te sach y ((nang x) or (trong van)) hoi. hieu va hac ((toc va) or (toc ta)) hanh vi cua tre*.