Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh van » thanh san, thanh toan, thanh phan
hieu tuc » hieu thuc, hieu thuoc, lieu thuc
hieu luc » hieu luat, hieu qua
cham duc » pham duc, cham soc, pham duy
van chua » va chua, van chia, van chu
chua tre » chua tri, cua tre, chua trieu
co sach » bo sach, cuon sach, hoc sach
sach ky » sac ky, sach y, sach ty
ky dong » ly dong, ky dang, ky cong
duc van » duc va, duc tan, duc manh
co hoi » co hoc, co loi

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach ky dong co hoi. ((hieu tuc) or (hieu luc)) cham duc van thanh van chua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ky dong co hoi. ((hieu tuc) OR (hieu luc)) cham duc van thanh van chua tre.
• Adding a wildcard symbol may retrieve word variants: co sach ky dong co hoi. ((hieu tuc) or (hieu luc)) cham duc van thanh van chua tre*.