Please refrain from limiting access to regular articles to administrators only. Only articles to which regular users do not need to contribute, such as Getting Started and the main page, and template pages that affect the entire wiki, should be protected thus, as we should be encouraging collaboration on and contribution to the wiki's articles.
If an article is experiencing heavy vandalism, please undo the edits and block the offenders. If the vandalism persists, please block new and unregistered users from editing the page. Only limit editing privileges to administrators as a last resort.