There are several ways to find and replace code in your solution using textual search. As opposed to searching for code items, textual search doesn't take code semantics into account and may render more unwanted results but it allows for more flexibility.
To search or replace text in the current document, press Ctrl+F/Ctrl+R or choose Edit | Find | Find/Replace in the menu.
To search or replace in the desired scope, press Ctrl+Shift+F/Ctrl+Shift+R or choose in the menu.
Press Ctrl+F3 on any word to find all occurrences of this word in the document.