I come across many community sites that have uploaded interesting PDF documents with a correct file name, for example: “Law and Economics 2014”, with the year and names of the publisher and author. How can I search for them specifically? and by the way, Yandex advanced search does not open, it says 404 error? You won`t find the file names through Google or any other search engine. Use Google to search for the title, however, when I try to search for them, it doesn`t find any. I try “site:vk.com “the file name” or “site:vk.com/communitypage “the file name”. I want to search for file names uploaded to vk.com on some community pages, PDFs for sure. The last one works sometimes, it all depends on how the information was published on VK etc. I know there are many PDFs that can be useful, but I only find them by chance when I come across them and see the filenames with these words. I want to be able to find PDFs whose names include the word “business” or “science,” for example. like “Economy and blah blah”.