How to redirect the new URL without changing to the old URL in address bar?

old URL:  \/tag\/(.*)                         www.mydomain.com/tag/women+cloth

new URL: /search?tag={1}             www.mydomain.com/search?tag=women+cloth

I want to keep the "www.mydomain.com/tag/women+cloth" in address bar of browser, is it possible ? thanks.

Hi,
 

OLD URL: 

http\:\/\/mydomain\.com\/tag\/(.*)

NEW URL:
http://mydomain.com/search?tag={1}