Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
hanh vai » hanh vi, hanh va, hanh tai
dang xay » dang van, van xay
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
vai cua » dai cua, hai cua, lai cua
hieu le » hieu ve, hieu ly, tieu le
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu he » hieu ve, hiem he, hieu hien
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky ((nang xa) or (dang xay)) hoi. ((hieu le) OR (hieu he)) nam thuc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((nang xa) OR (dang xay)) hoi. ((hieu le) OR (hieu he)) nam thuc va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((nang xa) or (dang xay)) hoi. ((hieu le) OR (hieu he)) nam thuc va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang xa) or (dang xay)) hoi. ((hieu le) OR (hieu he)) nam thuc va hanh vai cua tre*.