How to read files that contain a certain number/word in R?

I have a huge number of files and the filenames look like this:

 AL0201A0000500100day.1-1-2011
 AL0201A0000700100dymax.1-1-2011
 AL0201A0000900100day.1-1-2011
 AT0ILL10000400100day.1-1-1997
 AT0HBG10000700500hour8.1-1-1995

And I only want to read the files that contain for example 00007. The files are in different folders and subfolders.

How do I do that? I totally fail to use the * function in R. I know how to do that in Python, but I get nowhere in R. :/

Any suggestions?