Perhaps you should try some spelling variations:
thieu nien » thien nhien
ban hang » ngan hang
van hanh » van thanh, ban hanh, van anh
nien cac » vien cac, dien cac, bien cac
vai cua » dai cua, hai cua, lai cua
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cac vo » cac co, cac vi, cac bo
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: so sach ky ((nang xa) OR (nang ma)) hoi. thieu nien cac vo ((van hanh) or (ban hang)) vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((nang xa) OR (nang ma)) hoi. thieu nien cac vo ((van hanh) OR (ban hang)) vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((nang xa) OR (nang ma)) hoi. thieu nien cac vo ((van hanh) or (ban hang)) vai cua te".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((nang xa) OR (nang ma)) hoi. thieu nien cac vo ((van hanh) or (ban hang)) vai cua te*.