Basically what you want to do is not really possible. If the user knows the keystrokes they can still access the commands even if you hide the menu item. Plus, if you accessed the PDF in your browser, it is always saved somewhere temporarily, so you can find it there. If a user can access your PDF you can't do much to stop them from saving it. If you really really really want to restrict access, you can look into
Digital Rights Management, but it comes with a hefty price tag.