Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
sang tao » hang tai
tinh ve » trinh ve, tinh ven, dinh ve
cham so » cham soc, cham o, ham so
vu cham » va cham, vu kham, tu cham
hieu vu » hieu va, hieu ve, hieu su
sach ty » sach y, sach tu, xach tay
so may » co may, bo may, do may
ve cua » le cua, de cua, te cua
cua cu » cua chu, cua cau, cua su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ty) OR (sach thu)) ((mang may) or (sang tao)) hoi. hieu vu cham so may tinh ve cua cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach thu)) ((mang may) OR (sang tao)) hoi. hieu vu cham so may tinh ve cua cu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) OR (sach thu)) ((mang may) or (sang tao)) hoi. hieu vu cham so may tinh ve cua cu".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) OR (sach thu)) ((mang may) or (sang tao)) hoi. hieu vu cham so may tinh ve cua cu*.