The main index for finding articles on Canadian criminal law is the Index To Canadian Legal Literature (available on Westlaw). All of the journals mentioned below are indexed here.
To find papers from continuing legal education seminars, the Quicklaw database Canadian Law Symposia Index (CLSI) is helpful. Quicklaw Journals focuses on Canadian journals, and is both searchable and browseable.
LegalTrac also indexes some Canadian journals and would pick up articles about Canada in US journals.