Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
va danh » va dinh, va dan, dia danh
le lang » le tang, le xang, le bang
sai cua » dai cua, hai cua, lai cua
le dang » le tang, le dan, le quang
hieu va » lieu va, hieu qua
cao tuc » dao tuc, cao duc, cao suc
va hanh » van hanh, va thanh, ban hanh
va cao » va cac, va co, va dao
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((le lang) OR (le dang)) xa hoi. hieu va cao tuc ((va danh) or (va hanh)) sai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((le lang) OR (le dang)) xa hoi. hieu va cao tuc ((va danh) OR (va hanh)) sai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((le lang) OR (le dang)) xa hoi. hieu va cao tuc ((va danh) or (va hanh)) sai cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach ((le lang) OR (le dang)) xa hoi. hieu va cao tuc ((va danh) or (va hanh)) sai cua te*.