Perhaps you should try some spelling variations:
doanh dan » doanh ban, doanh van, doanh dao
hieu van » hieu va, thien van, lieu va
toc sach » hoc sach, doc sach, thuoc sach
va doanh » van doanh, vay doanh, va danh
van hac » van hoc, van ha, van hai
hac hoc » bac hoc, hoc hoc, cac hoc
lang xa » lang ha, dang xay, lang van
ty lang » tay lang, ty xang, ty hang
cua tu » cua tuc, cua su, cua cu

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