Perhaps you should try some spelling variations:
doanh dan » doanh ban, doanh van, doanh dao
va doanh » van doanh, vay doanh, va danh
tu sach » thu sach, su sach, te sach
ve cham » va cham, ve chat, vu cham
nang ma » tang ma, nang cao, mang may
dan cua » dan ca, ban cua, dai cua
sang ma » tang ma, sang tao, mang may
sach ky » sac ky, sach y, sach ty
ve cam » ve cac, va cam, ve cai
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: tu sach ky ((nang ma) OR (sang ma)) hoi. hieu ((ve cam) OR (ve cham)) duc va doanh dan cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang ma) or (sang ma)) hoi. hieu ((ve cam) OR (ve cham)) duc va doanh dan cua te~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang ma) or (sang ma)) hoi. hieu ((ve cam) OR (ve cham)) duc va doanh dan cua te*.