You can search multiple keywords with something like this:

    label:robotics + label:machine_learning

in the author search. But I don't know a way to narrow by country.

If you're really interested, you might be able to do some coding to get what you're after. Perhaps something like this:

http://biostat.jhsph.edu/~jleek/code/googleCite.r

or you can modify some of the code in the `scholar` package in `R`.