Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
hieu cua » hieu qua, dieu cua, bieu cua
dang xay » dang van, van xay
sach ty » sach y, sach tu, sach thu
thuc va » thuc vat, thuc dan, thuc day
cua nam » cua tam, cua ngan, cua nhan
su sach » so sach, vu sach
lang xa » lang ha, lang van
va dan » ca dan, va dao, va dau
dan va » doan va, dan ca, ban va
va cua » va chua, via cua, ca cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((lang xa) or (dang xay)) hoi. hieu cua nam thuc va dan va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang xa) OR (dang xay)) hoi. hieu cua nam thuc va dan va cua te.
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang xa) or (dang xay)) hoi. hieu cua nam thuc va dan va cua te*.