The Collaborative International Dictionary of English v.0.48:

Systematically \Sys`tem*at"ic*al*ly\, adv.
   In a systematic manner; methodically.
   [1913 Webster]

WordNet (r) 3.0 (2006):

systematically
    adv 1: in a systematic or consistent manner; "they
           systematically excluded women" [syn: systematically,
           consistently] [ant: inconsistently,
           unsystematically]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "systematically":
   always, at every turn, at regular intervals, at stated times,
   constantly, continually, every so often, harmoniously,
   intermittently, invariably, like clockwork, methodically,
   never otherwise, orderly, punctually, regularly, steadily,
   uniformly, without exception