You can use the search operator directly in the AdvancedSearch → Filter tab eg:
[search:title,text:some[tc-center]] … See the docs for the operator suffixes.
It will give you these results, which contain some system tiddlers.
To get rid of the system tiddlers you can do this
[search:title,text:some[tc-center]!is[system]] which gives you this result, that you can export with the export button
Since creating a good search term can be a lot of work, I did create the advanced-search-plus plugin, which allows me to store the filter expressions
Also see: [INTRO] Advanced Search Plus (ASP) - for advanced users and developers