Look in your portfolio (page_portfolio.php) funchtions…
Something like this:
// Custom Read More link
add_filter( 'excerpt_more', 'portfolio_read_more_link' );
add_filter( 'get_the_content_more_link', 'portfolio_read_more_link' );
add_filter( 'the_content_more_link', 'portfolio_read_more_link' );
function portfolio_read_more_link() {
return '<a class="button more-link" href="' . get_permalink() . '" rel="nofollow">Read More</a>';
}<!--formatted--><!--formatted-->
The LAST LINE >Read More< is the text to change. So you can make it >Read full article<