At the United Nations Security Council, China cast aside its longstanding policy of opposing sanctions against other nations. It voted to impose penalties on North Korea, its neighbor and onetime ally, for testing nuclear weapons. Officials and leading scholars are becoming a bit less hesitant to discuss what this all might mean. The documentary, on China’s main national network, uses the word rise constantly, including its title, “Rise of the Great Powers.” It endorses the idea that China should study the experiences of nations and empires it once condemned as aggressors bent on exploitation. “Our China, the Chinese people, the Chinese race has become revitalized and is again stepping onto the world stage,” Qian Chengdan, a professor at Beijing University and the intellectual father of the television series, said in an online dialogue about the documentary on Sina.com, a leading Web site. “It is extremely important for today’s China to be able to draw some lessons from the experiences of others,” he said. The series, which took three years to make, emanated from a Politburo study session in 2003. It is not a jingoistic call to arms. It mentions China only in passing, and it never explicitly addresses the reality that China has already become a big power. Yet its version of history, which partly tracks the work done by Paul Kennedy in his 1980s bestseller, “The Rise and Fall of the Great Powers,” differs markedly from that of the textbooks still in use in many schools.