Code
            string str = @"D:\新建文件夹.txt;图片文件\图片.jpg;D:\NEW\新闻;文件.txt夹\焦点;新闻;D:\科技;文件.doc夹\科技.doc";
            var s = str.Split(new char[] { ';' });

            var Out = new List<string>();

            for (int i = s.Length - 1; i >= 0; i--)
            {
                var b = false;
                var t = "";
                var j = i;
                for (; j >= 0; j--)
                {
                    if (t.Length > 0) t = ";" + t;
                    t = s[j] + t;
                    b = Path.IsPathRooted(t);
                    if (b) break;
                }
                i = j;
                if (b) Out.Add(t);
            }

            foreach (var f in Out)
            {
                Console.WriteLine(f);
            }
            Console.ReadLine();