Yahoo Inc. is ending its partnership with Amazon.com Inc., the top online seller of books, and creating a much larger link with Amazon rival Barnesandnoble.com. Terms of the deal, which was announced after the markets closed, were not disclosed. Santa Clara, Calif.-based Yahoo also announced a partnership to offer premium product placement and co-brand Internet access with Costco Wholesale Corp. The deal will offer free Internet access to Costco's 25 million members in the United States. Yahoo closed off 81 cents at $105.06 on Nasdaq. Costco fell $1.25 at $34.06 on Nasdaq. Barnesandnoble.com closed up 6 cents at $4.56, and Amazon closed off 81 cents at $42.81, both on Nasdaq.