Is Google search engine excludes some results to be shown?

Question

I am sure that I have searched terms in Google 2 or 3 years age, and too many results were found, and many of them have been downloaded. But now, with the same criteria, no results will be found!

My searches were based on searching specific terms in FTP servers. The results were directing me to FTP servers that contain that specific file, and in many cases, the neighbour files were also related. In that time the Google result list was rich and many sites were found, but now almost nothing. I have tried an advanced search with no results. It seems that Google is hiding the results since in some other search engine, many results can be found but it is very limited.

My question has two parts:

1. Does Google change his searching methodology to hide some results? Is there any way to say to Google to retrieve the old results?
2. If it is not possible, is there any alternative search engine to be used as a deep search engine, powerful as Google?

Answer 1

Yes, Google uses an algorithm to show you things that it may interest you, and so many thinks that it think it's not what you are looking for are not shown.

Mabye you can try Tools > All results > Verbatim, that it will "cancel" the Google search algorithm and show everything as it goes. Also you can try DuckDuckGo.

Answer 2

Yes, Google changes their search algorithm all of the time. One recent change was to de-emphasize known pirate sites in search.

Also, sites go down all of the time. It's entirely possible that the sites you're remembering no longer exist. They may also have taken steps to reduce what Google indexes.