Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
doanh va » doan va, doanh tai, doanh cua
va doanh » van doanh, vay doanh, va danh
sach thu » sach thue, sach thieu, sach tham
hieu van » thien van, lieu va, hieu ve
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
sach tu » cach tu, sach ty, sach uu
lang xa » lang ha, dang xay, lang van
va cua » va chua, via cua, ca cua

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

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