Perhaps you should try some spelling variations:
ban hanh » ban hang
sach ky » sach y, sach ty, sach kem
dao tuc » dao duc
tuc ban » thuc ban, truc ban, tu ban
hanh di » hanh vi, hanh de, hang di
cuu tre » cua tre, cau tren, cau treo
sac ky » cac ky, sai ky
va dao » ca dao
di cuu » di cau, di cua, dinh cuu
x hoi » o hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) OR (sac ky)) nang ((x hoi) or (xa hoi)). lieu va dao tuc ban hanh di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sac ky)) nang ((x hoi) OR (xa hoi)). lieu va dao tuc ban hanh di cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sac ky)) nang ((x hoi) or (xa hoi)). lieu va dao tuc ban hanh di cuu tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sac ky)) nang ((x hoi) or (xa hoi)). lieu va dao tuc ban hanh di cuu tre*.