Perhaps you should try some spelling variations:
co sach » bo sach, cuon sach, hoc sach
sach ly » sach y, sach lo, sach ty
ly hang » ly quang
hang xa » hoang xa, hang va, hang ca
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac nuoc
cac tac » cac toc, cac bac, cac dac
va danh » va dinh, va dan, va hanh
tai cua » thai cua, tri cua, dai cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ly hang xa hoi. hieu ve ((cac tuc) OR (cac tac)) va danh ((tai cua) OR (tai cuc)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach ly hang xa hoi. hieu ve ((cac tuc) OR (cac tac)) va danh ((tai cua) or (tai cuc)) tre~".
• Adding a wildcard symbol may retrieve word variants: co sach ly hang xa hoi. hieu ve ((cac tuc) OR (cac tac)) va danh ((tai cua) or (tai cuc)) tre*.