Perhaps you should try some spelling variations:
doanh dan » doanh ban, doanh van, doanh dao
hieu van » thien van, lieu va, hieu ve
va doanh » van doanh, vay doanh, va danh
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty lang » tay lang, ty xang, ty hang
lang ha » long ha
hieu va » lieu va, hieu qua
cac toc » cac toi, cac nuoc, cac thoi
toc va » hoc va, toc ta, tuc va
cua te » cua tu
cua su » qua su

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: te sach ty lang ha noi. ((hieu van) OR (hieu va)) cac toc va doanh dan ((cua te) OR (cua su))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty lang ha noi. ((hieu van) OR (hieu va)) cac toc va doanh dan ((cua te) or (cua su))~".
• Adding a wildcard symbol may retrieve word variants: te sach ty lang ha noi. ((hieu van) OR (hieu va)) cac toc va doanh dan ((cua te) or (cua su))*.