ClinicalTrials.gov is open, however it is being maintained with minimal staffing due to the lapse in government funding. Information will be updated to the extent possible, with priority given to processing registrations of new trials and critical updates to existing entries, such as trial status and contact information for enrollment. The agency will attempt to respond to urgent operational inquiries. For updates regarding government operating status see http://www.usa.gov.
Its completeness relies in part on the company reporting to them.