Unfortunately, we do not currently offer this feature. You can learn all about activities.search
at https://developers.google.com/+/api/latest/activities/search.
However, we are constantly looking to improve our APIs. Feel free to star this existing feature request in our Issue Tracker, and you will receive updates on this issue. https://code.google.com/p/google-plus-platform/issues/detail?id=33
Now that our Google+ Sign-In launch is complete, we will be using the Issue Tracker as our primary resource for developer bugs and feature requests.