Perhaps you should try some spelling variations:
cham duc » pham duc, cham soc, pham duy
su sach » so sach, vu sach
sach tu » sach thu, cach tu, sach ty
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu su » hieu sau, tieu su, hieu so
su cham » su pham, tu cham, vu cham
va chua » vua chua, ca chua, va chu
chua te » cua te, chua tu, chua xe

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 tu ((nang xa) or (lang xa)) hoi. hieu su cham duc ((va tinh) OR (may tinh)) va chua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tu ((nang xa) OR (lang xa)) hoi. hieu su cham duc ((va tinh) OR (may tinh)) va chua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach tu ((nang xa) or (lang xa)) hoi. hieu su cham duc ((va tinh) OR (may tinh)) va chua te".
• Adding a wildcard symbol may retrieve word variants: su sach tu ((nang xa) or (lang xa)) hoi. hieu su cham duc ((va tinh) OR (may tinh)) va chua te*.