Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
tu sach » thu sach, su sach, te sach
van cuu » van cau, van chu, van cu
sach ky » sac ky, sach y, sach ty
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cuu tre » cua tre, cau tren, cau treo
luc va » duc va, loc 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: tu sach ky ((nang xa) OR (nang ma)) hoi. hieu ve cham ((luc va) or (tuc va)) doanh van cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang ma)) hoi. hieu ve cham ((luc va) OR (tuc va)) doanh van cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) OR (nang ma)) hoi. hieu ve cham ((luc va) or (tuc va)) doanh van cuu tre*".