Analog and Asimovs only buy limited term electronic rights - it recently went up so now I think they can keep about nine months or so. I'm getting paid for an editing contract right on the 31st, so with any luck I might be able to get another Asimovs subscription (and Interzone) and then see about extending the Analog further. I like to keep my Analog subscription sitting with more than a year to go.
(I actually managed to read the entire decade of the fifties for Analog - then Astounding - in order one year.)