A large catalogue of Russian dissertations is now available online. There is a substantial selection of archaeology titles, many, perhaps most of them otherwise unavailable. The titles listed appear to be machine translated into English. Twenty-five page samples of each title are offered, but were not available for any that I tried.
The service promises, for a reasonable fee, to be able to supply a pdf of the each dissertation in one day, or for slightly more a pdf + machine translation in two days. Prices for pdf + professional translation depend on the size of the work and requires 5-10 days.
I have not yet tried to order a copy. If anyone has, I would appreciate comment below.