Perhaps you should try some spelling variations:
cac treo » cau treo, cac trieu, cac tieu
nam thuc » nam thuoc, am thuc, nam thu
dan vai » dan va, dan tai, dan vat
thuc va » thuc vat, thuc dan, thuc day
hieu ha » hieu hoa, hieu va, hieu ca
sach ky » sac ky, sach y, sach kem
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, sach thu
va dan » ca dan, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((sach ky) or (sach ty)) lang xa hoi. hieu ha nam thuc va dan vai ((cac treo) OR (cac tro))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((sach ky) OR (sach ty)) lang xa hoi. hieu ha nam thuc va dan vai ((cac treo) OR (cac tro)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((sach ky) or (sach ty)) lang xa hoi. hieu ha nam thuc va dan vai ((cac treo) OR (cac tro))".
• Adding a wildcard symbol may retrieve word variants: hoc ((sach ky) or (sach ty)) lang xa hoi. hieu ha nam thuc va dan vai ((cac treo) OR (cac tro))*.