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

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 dai ((su triet) OR (su viet))~.
• 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 dai ((su triet) OR (su viet)).
• 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 dai ((su triet) OR (su viet))".
• Adding a wildcard symbol may retrieve word variants: toc sach va ((nang xa) or (lang xa)) hoi. hieu qua cham duc va danh dai ((su triet) OR (su viet))*.