[Mediawiki-l] about searching in mediawiki

[hzh华志昊]

zh.wikipedia.org and other wikipedias provide a powerful searching tool,which give results in relevance rank.And I have looked for the tool for days,but nothing found.Is it still not public?
 
And the second question is also about searching, while keywords contain asia characters ,my mediawiki return some not matched results.I guess an asia word is splitted into several.Is there any configuration about this,or solution?I found other mediawikis used in china got the same problem.
 
Maybe I can't express myself in English, so any help will be appreciated.