Look around for the websites of the companies that do work in your field or interest and try to find contact info for HR (who are very often dumb esp in cases of big companies) or preferably the manager of the department that you would like to be in and shoot out your tailor made resume even if they have no openings announced on their website or anywhere else. At the worst you will get a "no" or "sorry", that you have nothing to lose.

References and  contacts very often do the magic if you could find any.