Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh hoi » hanh thoi, hanh noi, hanh hoa
nang ma » tang ma, sang ma, nang cao
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cao duc » dao duc, cao suc, giao duc
duc van » duc va, duc tan, duc manh
hoi cua » hoi chuc
cua tre » cua te, cuu tre, cua triet
va cao » va cac, va co, va dao
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: thu ((sach y) or (sac ky)) ((nang ma) or (lang xa)) hoi. hieu va cao duc van hanh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach y) OR (sac ky)) ((nang ma) OR (lang xa)) hoi. hieu va cao duc van hanh hoi cua tre.
• Adding a wildcard symbol may retrieve word variants: thu ((sach y) or (sac ky)) ((nang ma) or (lang xa)) hoi. hieu va cao duc van hanh hoi cua tre*.