Perhaps you should try some spelling variations:
vat doanh » van doanh, vay doanh, va doanh
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
doanh va » doan va, doanh tai, doanh cua
dang xa » dang xay, dang ha, dang va
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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

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