https://scholar.google.co.uk/Is good for searching open source papers, unfortunatly it's been about 5 years since I finished my PhD, so I don't have anymore access, or really any good ideas. I remember it being very difficult to get hold of anything not subscribed to though.
You didn't say what your subject was (or country) so I don't know what your funding is like, but have you looked into getting them bought as part of your grant?
If I was still at my uni I would have hooked you up, good luck bro :)
Out of interest what is the subject on?