These stocks have helped the Dow hit a record high this year and are still great picks for long-term investors.The Dow Jones Industrial Average is having a record year. The widely followed index broke the 40,000 mark in May for the first time. This week, the Dow topped 42,000 -- again setting an all-time high.Should investors check out some of the top components of the Dow Jones index? I think so. Here are three magnificent Dow stocks to buy right now.1. AmazonAmazon (AMZN -0.71%) is handily beating the Dow ...