Perhaps you should try some spelling variations:
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
lam thuc » lam thuoc, am thuc, nam thuc
cua tre » cua te, cuu tre, cua triet
hang di » hang doi, hang vi, hang dien
hanh di » hanh vi, hanh de, danh di
thuc va » thuc vat, thuc dan, thuc day
van lam » van nam
lang xa » lang ha, lang van
sac ky » cac ky, sai ky
tu sac » tu sach, tu cac, tu san

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 ((lang xa) OR (dang xay)) hoi. hieu van lam thuc va ((hanh di) or (hang di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((lang xa) OR (dang xay)) hoi. hieu van lam thuc va ((hanh di) OR (hang di)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((lang xa) OR (dang xay)) hoi. hieu van lam thuc va ((hanh di) or (hang di)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((lang xa) OR (dang xay)) hoi. hieu van lam thuc va ((hanh di) or (hang di)) cua tre*.