Perhaps you should try some spelling variations:
doanh dai » doanh tai, doanh dao, doanh giai
lang van » dang van, tang van, hoang van
dang xay » dang van
hieu van » hieu va, thien van, lieu va
va doanh » van doanh, vay doanh, va danh
te sach » toc sach
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, van bac
cac toc » cac toi, cac nuoc, cac thoi
toc va » hoc va, toc ta, tuc va
cua te » cua tu

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