In most cases, the search result is going to provide an excerpt for content in both pages and posts. If the content is protected, users will be prompted for login (if they aren't already) when they click to read the entire article.
If you are getting full content and not excerpts in your search results, you may need to make some edits to your theme's search results template (or settings). There are many ways to do this. Depending on your theme, it may not be advisable to do direct edits (many themes are now upgradeable via the wp admin, and therefore any changes are likely to be overwritten). In that case, you might use some customizations added to your functions.php file.
Here is a sample to set excerpts at a specific length:
// set the number to whatever number of
// words you want the excerpt to be.
Here's some that will trim it at the 'more' tag (must be using the 'more' tag on all protected content for this to work):
$content = the_content;
$len = strpos($content, 'more');
$len = $len-10;
Hope this helps and/or gives you some ideas.