Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cua triet, dua tren
duc ban » duc tan, duc van, dua ban
van cao » van dao, van bao, van hao
ty hang » ly hang, ty xang, thi hang
ty lang » tay lang, ty xang, tu lang
cuu tre » cau tren, cau treo

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty lang) OR (ty hang)) xa hoi. hieu van cao duc ban thanh van ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty lang) OR (ty hang)) xa hoi. hieu van cao duc ban thanh van ((cua tre) or (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty lang) OR (ty hang)) xa hoi. hieu van cao duc ban thanh van ((cua tre) or (cuu tre))*.