Ctrl + W is the shortcut for searching. The same effect can be achieved by pressing the F6 key. After entering the search term, press Enter. To repeat the search, issue Alt + W, and to search the previous occurrence, press Alt + Q. In this menu, you can select earlier searches using the arrow up/ down keys.

To toggle backwards searching, you need to press Alt + B in the search dialog.

For more shortcuts, press F1