By Eduardo Baptista BEIJING (Reuters) – Chinese military bodies, state-run artificial intelligence research institutes and universities have over the past year purchased small batches of Nvidia semiconductors banned by the U.S. from export to China, a Reuters review of tender documents show. The sales by largely unknown Chinese suppliers highlight the difficulties Washington faces, despite its bans, in completely cutting off China’s access to advanced U.S. chips that could fuel breakthroughs in AI and sophisticated computers for its military. Buying or selling high-end U.S. chips is not illega…