As can be expected there are search/replace features available, either from the toolbar, or the menu. By default the find/replace just performs a straight forward comparison on the strings. Once ready to start search/replacing click the Find Next button, this will jump to the next occurance of the string. If you are replacing then you can click the Replace button to perform the action, or the Replace All button to replace every occurance without prompting.
Sometimes matching against a string isn't enough, therefore Screem supports the use of regular expressions in the find string. This can be enabled by clicking on the checkbutton.
Project wide search/replace is also provided. A list of all files where a match is found is shown in the find/replace dialog. Clicking on a file in that list will view that file and allow you to perform the find/replace as usual.