Increase selection number of pages and number of blog

I use Multisite Content with 108 blog
1. select actions : ok
2. select source : ok
3. select items
There is 269 elements and I got 27 arrow selections to select all elements. How can I do to done it in a lone action ??
Its the same for blog, very contraignant, is there a way to select all in one time ?
Thank you