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