A database of doctor discipline and malpractice records blocked by the federal government in September was made public again Wednesday with new restrictions for anyone who wants to use it. Before downloading the public file of the National Practitioner Data Bank maintained by the U.S. Health Resources and Services Administration, users must agree not to identify individual doctors and to delete or return any data at the request of the government agency. The data bank is a record of malpractice and discipline records intended for hospitals to check doctors' backgrounds. The public file of the data was stripped of doctors' names but has been used for years by reporters and researchers to analyze trends and identify problem doctors by cross-referencing with court and medical board records.