Custom Post Query with pagination in wordpress

/*
www.wp-tutorials.com
*/
<?php
  $temp = $wp_query;
  $wp_query = null;
  $wp_query = new WP_Query();
  $wp_query->query('showposts=-1&post_type=doctor-items'.'&paged='.$paged);

  while ($wp_query->have_posts()) : $wp_query->the_post();
?>


<!-- content -->

<!-- Content -->


<?php endwhile; ?>

<div class="blog_post_pagi"><?php the_posts_pagination();?> </div>

<?php
  $wp_query = null;
  $wp_query = $temp;  // Reset
?>