Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
duc van » duc va, duc tan, duc manh
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cao duc » dao duc, cao suc, giao duc
va cao » va cac, va co, va dao
sac ky » cac ky, sai ky
de su » den su, ve su, de tu
da su » dan su, dat su, va su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach y) or (sac ky)) nang xa hoi. hieu va cao duc van hanh ((de su) or (da su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach y) OR (sac ky)) nang xa hoi. hieu va cao duc van hanh ((de su) OR (da su)) triet.
• Adding a wildcard symbol may retrieve word variants: tu ((sach y) or (sac ky)) nang xa hoi. hieu va cao duc van hanh ((de su) or (da su)) triet*.