Perhaps you should try some spelling variations:
cuon sach » duong sach, cuoc cach, co sach
van hang » van khang, van hoang, van thang
xang xa » lang xa, mang xa, ang xa
hieu ve » hieu va, hieu van
cao luc » bao luc, cao duc, cao suc
va hang » va nang, va lang, va hanh
y xang » ty xang
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: cuon sach y xang xa hoi. ((hieu ve) or (hieu qua)) cao luc ((va hang) OR (van hang)) dai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: cuon sach y xang xa hoi. ((hieu ve) OR (hieu qua)) cao luc ((va hang) OR (van hang)) dai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "cuon sach y xang xa hoi. ((hieu ve) or (hieu qua)) cao luc ((va hang) OR (van hang)) dai cua tu".
• Adding a wildcard symbol may retrieve word variants: cuon sach y xang xa hoi. ((hieu ve) or (hieu qua)) cao luc ((va hang) OR (van hang)) dai cua tu*.