aakk9999 - 2:48 pm on Jun 20, 2012 (gmt 0)
If your canonical page is domain root, then the link rel "prev" should point to root, not to "/1".
<link rel="prev" href="/1"
It would be perhaps the best to stop the search URLs via robots.txt. Of course, providing that there are other ways of accessing the product pages.
if your site has a search function and you have a pagination, then again i'm not sure which one to use: canonical or prev-next