RT Journal Article SR Electronic T1 Higher Efficacy of Intrathecal Morphine in Female versus Male Rats JF Regional Anesthesia & Pain Medicine JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP 28 OP 28 DO 10.1136/rapm-00115550-199924031-00028 VO 24 IS Suppl 1 A1 Brian K. Tsang A1 Zhi He A1 Ing K. Ho A1 John H. Eichhorn YR 1999 UL http://rapm.bmj.com/content/24/Suppl_1/28.abstract AB