Perhaps you should try some spelling variations:
dang xay » dang van, van xay
va thanh » gia thanh, ban thanh, va tinh
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va danh, ban hanh
hieu va » lieu va, hieu qua
vi cua » vai cua, di cua
tu san » thu san, tu ban, tu can
san ky » sang ky, van ky, dan ky
va cau » van cau, va cac, va dau

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: tu san ky ((nang cao) OR (dang xay)) hoi. hieu va cau truc ((va hanh) OR (va thanh)) vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu san ky ((nang cao) or (dang xay)) hoi. hieu va cau truc ((va hanh) OR (va thanh)) vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu san ky ((nang cao) or (dang xay)) hoi. hieu va cau truc ((va hanh) OR (va thanh)) vi cua tre*.