Perhaps you should try some spelling variations:
doanh ban » doanh bat, doanh van, doanh nhan
thu sach » tu sach, thuat sach, thuoc sach
va doanh » van doanh, vay doanh, va danh
chat hoa » thuat hoa, chat va, chat huu
chat hoc » chat thom, cho hoc, vat hoc
sach ky » sac ky, sach y, sach ty
ban cua » ban quan
hieu ve » hieu va, hieu van
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
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: thu sach ky ((nang ma) or (sang ma)) hoi. hieu ve ((chat hoc) OR (chat hoa)) va doanh ban cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang ma) OR (sang ma)) hoi. hieu ve ((chat hoc) OR (chat hoa)) va doanh ban cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang ma) or (sang ma)) hoi. hieu ve ((chat hoc) OR (chat hoa)) va doanh ban cua te*".