Perhaps you should try some spelling variations:
van doanh » toan doanh, van dong, van thanh
toc sach » hoc sach, doc sach, thuoc sach
bac truc » ba truc, bac trung, sach truc
dang xay » dang van, van xay
va doanh » vay doanh, va danh, hoa doanh
hieu van » hieu va, thien van, lieu va
van bac » van ban, van bao, van hac
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
va cua » va chua, via cua, ca cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky ((nang xa) or (dang xay)) hoi. hieu van bac truc ((va doanh) OR (van doanh)) va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((nang xa) OR (dang xay)) hoi. hieu van bac truc ((va doanh) OR (van doanh)) va cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((nang xa) or (dang xay)) hoi. hieu van bac truc ((va doanh) OR (van doanh)) va cua te*".