this is not built in functionality, however you could try to accomplish this in a couple ways. First you could try setting up a report that does a query to the DB like
SELECT DocumentName,DocumentNamePath FROM CMS_Document WHERE CONTAINS(DocumentContent, '@inputparameter')
However the "CONTAINS" will require the CMS_Document table to be full-text indexed in order to work, you could try using a "LIKE" statement instead however the performance may be really bad here.
Another solution could be to use a page crawler search index on all pages in your site, then you could use smart search webparts on a custom module ui page to search and create some report via a custom module.