Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
so sach » so sanh, bo sach, co sach
vang xa » mang xa, ang xa, dang xay
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
ve nam » he nam, va nam, le nam
di cua » doi cua, de cua, do 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: so sach y ((vang xa) OR (lang xa)) hoi. hieu ve nam thuc van hanh ((di cua) OR (dai cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y ((vang xa) OR (lang xa)) hoi. hieu ve nam thuc van hanh ((di cua) or (dai cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: so sach y ((vang xa) OR (lang xa)) hoi. hieu ve nam thuc van hanh ((di cua) or (dai cua)) tre*.