Perhaps you should try some spelling variations:
dang xay » dang van, van xay
cau thuc » cau truc, cuu thuc, can thuc
vat hanh » vat thanh, van hanh, va hanh
hieu va » lieu va, hieu qua
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai 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 sac ky ((nang cao) OR (dang xay)) hoi. hieu va cau thuc vat hanh vi ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((nang cao) or (dang xay)) hoi. hieu va cau thuc vat hanh vi ((cua tre) OR (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang cao) or (dang xay)) hoi. hieu va cau thuc vat hanh vi ((cua tre) OR (cuu tre))*.