Fill in the text you would like to search for and then press the Find button. Export Explorer will look through all the source code entities and try to match your specified text. Each successful match is displayed in the listview in the middle of the window. The total number of matches is shown above. When there is more than one match in a particular line of code each match is shown as a separate entry in the listview. The entity matching the currently highlighted listview item is displayed below, with the matching text highlighted.
You can use regular expressions when searching - see the page Regular Expressions for details.