From yesterday Bing provides the list of links for every Yahoo search, so, for example, to view the backlinks of your site in Yahoo you can try using the new Yahoo search queries (current Bing ones):
Or you can get the best and most complete overview of back-links to your website that are known by Yahoo/Bing by using the Bing Webmaster Tools
And you need to download the Bing Search Query Language Guide from Microsoft to know all the new Yahoo search queries. You can do it here
If you know a better way to check your back-links in Yahoo, please do share it in the comments below!