C# - How to get data from mywebsearch(Search Engine)

I have been trying to make a tool that I enter keyword and it will automatically do this:

int.search.mywebsearch.com/mywebsearch/GGweb.jhtml?searchfor=Keyword
then ---> Scrape all the urls in the page

however, when I go to regexxr or regex101, it seems like the urls not there and I can't use regular expression to get it. How can I scrape something that using WebClient.downloadstring(url) can't download

Code:

WebClient wc = new WebClient();
        foreach(string s in Keywords)
        {
            string url = wc.DownloadString("https://int.search.mywebsearch.com/mywebsearch/GGmain.jhtml?&searchfor=" + s);
            MatchCollection mc = Regex.Matches(url, @""); // Didn't write any regex yet
        }