Well by default, blogger doesn't provide one. So you have to make it yourself. So lets have a tutorial on it.
1. Go to Layout>Edit HTML and backup your template and expand it.
2. Find </head> and just bellow it add the following codes
<style>the style tags are necessary cause without these tags it will not work.
<b:if cond='data:blog.pageType == "item"'>
3. Find <data:post.body/>
and just bellow it add the following;
<b:if cond='data:blog.pageType != "item"'>You can change "Read more..." to your liking.
<a expr:href='data:post.url'>Read more...</a>
4. Preview your template for errors and save it.
5. Go to Settings>Formatting and add the following codes
Begin your postin "post template" and save it.
<span class="fullpost">And here is the rest of it.
Write the first paragraph in "Begin your post" and the rest in "And here is the rest of it".
Note: There is a limitation to this Even if you want a "full view" for a particular post, the "Read more..." option will be still be there. It's upto you how to use it...
Try it! Working? Then Subscribe to Simple Blogger Tutorials.
Also see Adding Custom Favicon to Blogger.