Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
dung sai » dung tai, dung va, dung dat
tu sach » thu sach, su sach, te sach
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
ve cam » ve cham, ve cac, va cam
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: tu sach ky ((nang ma) or (sang ma)) hoi. hieu ve cam duc va ((doanh van) or (dung sai)) cua te~.
• 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 duc va ((doanh van) OR (dung sai)) cua te.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang ma) or (sang ma)) hoi. hieu ve cam duc va ((doanh van) or (dung sai)) cua te*.