>I'm wondering, how can I search in articles content? For instance, I know that Sergey Berezniker published PADX functions implementation in one of his SQL columns (if my memory serves me right), but I don't remember which one and don't know how to find it quickly...

As Sergey mentioned, there is the All Articles link on the site. However, in the case you already know the authors, right here from the Universal Thread, you can view the member's profile and click on Contribution to get all content submitted by the author.