Perhaps you should try some spelling variations:
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
tu sach » thu sach, su sach, te sach
sach vu » sach va, sach tu, sach uu
su hien » su kien, su tien, thu hien
nang xa » nang x, lang xa, nang ma
vu nang » vuc nang, va nang, vu dang
va cao » va cac, va co, va bao
va dao » ca dao
ve su » va su

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 vu nang xa hoi. hieu ((va cao) OR (va dao)) xuc ((van hanh) or (ban hanh)) ve su hien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang xa hoi. hieu ((va cao) OR (va dao)) xuc ((van hanh) OR (ban hanh)) ve su hien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang xa hoi. hieu ((va cao) OR (va dao)) xuc ((van hanh) or (ban hanh)) ve su hien".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang xa hoi. hieu ((va cao) OR (va dao)) xuc ((van hanh) or (ban hanh)) ve su hien*.