Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
dua tren » dung tren
thanh vi » hanh vi, thanh va, thanh ve
hieu van » hieu va, thien van, lieu va
sach ky » sach y, sach ty, sach kem
duc ban » duc tan, duc van, dua ban
cao duc » dao duc, cao suc, giao duc
van cao » van dao, van bao, van hao
nang xa » nang x, lang xa, nang ma
cuu tre » cua tre, cau tren, cau treo
sac ky » cac ky, sai ky

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 xa hoi. hieu van cao duc ban thanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sac ky)) nang xa hoi. hieu van cao duc ban thanh vi ((dua tren) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sac ky)) nang xa hoi. hieu van cao duc ban thanh vi ((dua tren) or (cuu tre))*".