When using the advancedSearch form on beta, no search results are shown.
Weirdly enough on our test wiki, you have results in both cases (but there you should use the phrase "Hilfe zur Benutzung und Konfiguration" so that something can be found ;) )
Example Links:
- Not working advanced search:
- Working regular search https://deployment.wikimedia.beta.wmflabs.org/w/index.php?search=This+is+the+central+wiki&title=Special:Search&go=Go&searchToken=5qur4x49r8j8wb2b9lofwt32x