Specifically just the 400 best/recent ones. Google will never return more than 400 results for a query despite reporting ~80,000,000 results. If you click next enough it will run out after showing you ~38 pages of 10 results or almost 4 pages of 100 results.

This is the intended behavior. It kind of ruins serendipitious web surfing via search. I look through 4 pages of 100 results in less than a minute and the web as google search presents it just feels so shallow now.