search results shows the full post

I think it has to do with your theme’s search.php. Do you use <?php the_excerpt(); ?> for the search result?

actually I dont know about this , how can I know it???

I searched for this code in the search file but i cannot find it

@queeneve,
It really depends on how your theme handle the search result. Some theme might use get_template_part() to show the result.

You can try using other theme, eg. the default tewntyeleven theme it use get_template_part() to get the search content from the content.php file. Inside content.php file, you will see

<?php if ( is_search() ) : // Only display Excerpts for Search ?>
		<div class="entry-summary">
			<?php the_excerpt(); ?>
		</div><!-- .entry-summary -->

Just for your reference. Hope this help.

Thanks for your reply , I found an option in the theme settings to use either the whole content or the excerpts

Thanks