Search help from help module

When I want to learn more about a topic, I'm happy to check out a help window, but it would be even better if the window itself had a search function (in the title bar?) for narrowing the results or finding more about a topic.  If not in the title bar, would it be possible to include a search box on every page?  Yes, it might require scrolling down to find it (less than ideal) but it seems more intuitive than returning to the menu bar and navigating through the help system using that avenue.