A large Aperture Library can contain thousands of Projects, Folders and Albums, but within aperture there is no way to search for those containers by name.

In Aperture Assistant go to Other Tasks>Find Containers... to search by name. As you type text into the search field, the field below will display all the Projects, Folders and Albums that contain that text in their name or in the names of their 'parent' containers.

To go to a specific container within the list, you can either double-click on it in the list, or select it and hit the Return key, or select it and click on the Reveal button.

Note - due to the way Aperture Assistant searches, entering 'album' will show all Albums even if they don't contain 'album' in their displayed name. In the same way, 'smart' will bring up all Smart Albums and 'project' will show all Projects.