When we do a Google search for a specific type of file, it gathers all types of the results, be it of any type. Here I would like to share a tweak which you can use to customize your Google search for finding specific type of file.
The syntax is (Use the command without <>)
filetype:< file type > <search term>
For example if you are searching for a PDF format files type filetype:pdf mobiletechnology, you can see the result with the file type that you mentioned.
Similarly you can search for any type of file like ppt, doc etc…