The Text Search view can be used to search through all string values within the currently open model. The view is opened by default in the bottom part of the screen, but you can otherwise open it from Window > Show View > Text Search. Enter a regular expression to search over and hit enter to start the search. This is using a SPARQL query using FILTER regex internally, and will walk up to the root of any blank node tree, if necessary. Double-clicking a result row navigates to the resource holding the value.