Half a second is enough for Google to process the search terms you enter and show all relevant sites, but the reality hiding behind the process what we see is very much complicated. .
In the following video, the Matt Cutts of Google explains the science behind the functioning of the leading search engine in the world:
According to his words, there are three things you should do if you want to create a proper search engine:
“First, to scan the Internet and in-depth deixodika secondly to classify pages, and thirdly to show the most relevant of these.”