Perhaps you should try some spelling variations:
su sach » so sach, vu sach
xa hang » va hang, xa bang, ban hang
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
xa hung » ba hung, ha hung, la hung
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
cac toc » cac toi, cac nuoc, cac thoi
va cua » va chua, via cua, ca cua
ve cac » va cac, vien cac
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: su sach ky ((nang ma) or (sang ma)) hoi. hieu ve cac toc ((xa hang) OR (xa hung)) va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang ma) OR (sang ma)) hoi. hieu ve cac toc ((xa hang) OR (xa hung)) va cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang ma) or (sang ma)) hoi. hieu ve cac toc ((xa hang) OR (xa hung)) va cua te*".