【单选题】187 / 390强度安全系数表达式为?AK=N/NjxK=N/N_{jx}K=N/NjxBK=Njx/NK=N_{jx}/NK=Njx/N正确CK=M/NK=M/NK=M/NDK=N⋅NjxK=N\cdot N_{jx}K=N⋅Njx参考答案B参考解析K=Njx/NK=N_{jx}/NK=Njx/N。