Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
thu sach » tu sach, thuat sach, thuoc sach
sach thu » sach thue, sach thieu, sach tham
van cua » vang cua, ban cua, dan cua
vu cham » va cham, vu kham, tu cham
hieu vu » hieu va, hieu ve, hieu su
lang xa » lang ha, dang xay, lang van
bang xa » bang va, mang xa, ang xa
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach thu ((bang xa) OR (lang xa)) hoi. hieu vu cham ((xuc va) or (tuc va)) doanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach thu ((bang xa) OR (lang xa)) hoi. hieu vu cham ((xuc va) OR (tuc va)) doanh van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach thu ((bang xa) OR (lang xa)) hoi. hieu vu cham ((xuc va) or (tuc va)) doanh van cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach thu ((bang xa) OR (lang xa)) hoi. hieu vu cham ((xuc va) or (tuc va)) doanh van cua tre*.