Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dang xay » dang van, van xay
sach ky » sac ky, sach ty, sach kem
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
cac loc » cac lop, cac toc, cac hoc
van cac » van hac, van cau, van bac
cua tre » cua te, cuu tre, cua triet
loc va » hoc va, luc va
di cua » dai cua, doi cua, de 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: te ((sach ky) OR (sach y)) ((nang x) OR (dang xay)) hoi. hieu van cac loc va hanh di cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) OR (sach y)) ((nang x) or (dang xay)) hoi. hieu van cac loc va hanh di cua tre~".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) OR (sach y)) ((nang x) or (dang xay)) hoi. hieu van cac loc va hanh di cua tre*.