Perhaps you should try some spelling variations:
doanh vang » doanh van, doanh sang, doanh quang
tham thuc » nham thuc, pham thuc, tam thuc
vang cua » mang cua, hang cua, tang cua
va doanh » van doanh, vay doanh, va danh
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
ve tham » va tham, ve cham, vi tham
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
mang xa » mang may, dang xay, mang cua
nang xa » nang x, nang ma, ang xa
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y ((((nang xa) OR (mang xa))) or (lang xa)) hoi. hieu ve tham thuc va doanh vang cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((((nang xa) OR (mang xa))) OR (lang xa)) hoi. hieu ve tham thuc va doanh vang cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((((nang xa) OR (mang xa))) or (lang xa)) hoi. hieu ve tham thuc va doanh vang cua tre*".