Perhaps you should try some spelling variations:
dang xay » dang van, van xay
thuc dan » thuc hanh, hoc dan, thuc vat
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc day
vi cua » vai cua, di cua
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
ve nam » he nam, va nam, le nam

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 ve nam ((thuc va) OR (thuc dan)) hanh vi 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 ve nam ((thuc va) OR (thuc dan)) hanh vi 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 ve nam ((thuc va) OR (thuc dan)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang xa) or (dang xay)) hoi. hieu ve nam ((thuc va) OR (thuc dan)) hanh vi cua tre*.