Are you searching in the Knowledge Management Search? If so you are able to type Hello AND Man. This should work as you want.
Please let me know if this is what you were hoping for.
thanks for your response.
the idea is to have the same result with AND operator but without specify it.
today in Knowledge Management Search :
hello man ~ hello OR man
is it possible to change implicit OR opérator to implicit AND opérator
hello man ~ hello AND man.
I'm afraid that I don't think that you can change the default for this. If you feel this is important for you please raise this on the Enhancement Portal and hopefully other people will also agree and vote for it.