Welcome to Walmart. The nurse will be right with you. Walmart, the nation's largest retailer, has spent years trying to turn some of its millions of customers into patients, offering a simple menu of medical services that consumers can buy along with everything from a bag of chips to a lawn mower. Now, the store is making an aggressive push to become a one-stop shopping destination for medical care. The company has opened five primary care locations in South Carolina and Texas, and plans to open a sixth clinic in Palestine, Tex., on Friday and another six by the end of the year.