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 » lang xa, mang xa, ang xa
hieu ve » hieu va, hieu van
y vang » ly vang
ve nam » he nam, va nam, le nam
di cua » doi cua, de cua, da cua
do cua » doi cua, co cua, de 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 hoi. hieu ve nam thuc van hanh ((((di cua) OR (do cua))) OR (dai cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y vang xa hoi. hieu ve nam thuc van hanh ((((di cua) OR (do cua))) or (dai cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: so sach y vang xa hoi. hieu ve nam thuc van hanh ((((di cua) OR (do cua))) or (dai cua)) tre*.