Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cham duc » pham duc, cham soc, pham duy
qua cham » qua hai, qua cac, va cham
su triet » su viet, su tien, ve triet
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
sach va » sach xa, sach ha, sach dao
va danh » va dinh, va hanh, dia danh
va dan » ca dan, va dao, va dau
dai su » dai sua, dai so, dan su

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach va ((nang xa) or (lang xa)) hoi. hieu qua cham duc ((va danh) OR (va dan)) dai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach va ((nang xa) OR (lang xa)) hoi. hieu qua cham duc ((va danh) OR (va dan)) dai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach va ((nang xa) or (lang xa)) hoi. hieu qua cham duc ((va danh) OR (va dan)) dai su triet".
• Adding a wildcard symbol may retrieve word variants: toc sach va ((nang xa) or (lang xa)) hoi. hieu qua cham duc ((va danh) OR (va dan)) dai su triet*.