Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
duc van » duc va, duc tan, duc manh
cao duc » dao duc, cao suc, giao duc
van cao » van dao, van bao, van hao
va cuu » va chu, va huu
va cau » van cau, va cac, va dau
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: toc sach ky nang ((x hoi) or (xa hoi)). hieu van cao duc van thanh ((va cuu) OR (va cau)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang ((x hoi) OR (xa hoi)). hieu van cao duc van thanh ((va cuu) OR (va cau)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang ((x hoi) or (xa hoi)). hieu van cao duc van thanh ((va cuu) OR (va cau)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang ((x hoi) or (xa hoi)). hieu van cao duc van thanh ((va cuu) OR (va cau)) tre*.