A Single Intravenous Injection of Oxycodone Hydrochloride In The Treatment of Acute Post-operative Pain after Laparoscopic Rectal Tumor ResectionChunlu Zhang, Jiali Ding, Bin Wang and Peng ChenBIO Web Conf., 8 (2017) 01055DOI: https://doi.org/10.1051/bioconf/20170801055