UA search is or-based?

It seems like the searching function in Answers searches for any page containing any of the words in the search.

So searching for "rigidbody" gives ~17.000 results. Searching for "rigidbody velocity" gives ~21.000 results. Searching for "rigibody velocity script" gives ~101.000 results.

This is not how a search bar should work. When a user enters several words, they expect the search to become narrower, not wider. I assume that the most relevant results (ie. containing all search terms) will show up first, so for something like "rigidbody velocity script", this won't be a problem. If a user searches for something with very few (or no) results that match all of the words, they'll get a bunch of irrelevant results instead of a "no results" page, which would be a lot more helpful.

Is this a bug, or intentional behaviour?