The Homepage Excerpts plugin can be used to reduce this duplicate content while keeping full posts on the homepage. Suppose you have 8 full posts on the homepage. Once you activate the plugin you will have the option to select how many posts to display fully in the homepage. The options will go from 1 up to 8. If you select 8, all your posts on the homepage will keep being displayed fully while all the other posts (the ones on page two, three, four and so on) will turn into excerpts.
Homepage Excerpts, Plugin, WordPress Plugin, Post, Excerpt