Where are you typing those?
It sounds like you're trying that at qrz.com but they look like Google searches. I don't think the search engine at qrz.com handles that site: type language.
Those searches work just fine at Google and I think it's the better way to go anyway. New content from qrz.com seems to be visible on Google within hours.
The search on most sites suck and qrz.com is no real exception. The reason is that most sites try to search the content in the database which works okay for smaller sites but falls apart with lots of content. The good way for a web site to implement its own search is to use something like
Solr or
Elastic Search. That's exactly what I've spent most of this week doing for a big site that I look after.