convert htaccess rules into nginx

i have a big problem to convert this HTACCESS rules into Nginx how to implement first two lines and QUERY_STRING variable ?

RewriteCond %{SCRIPT_FILENAME} !-f
RewriteCond %{SCRIPT_FILENAME} !-d
RewriteRule ^([a-zA-Z0-9_/.]+)$ index.php?route=$1&%{QUERY_STRING} [L]