简述人机工程学的定义?
直立茎
现有 class Beverage { Beverage () { System.out.print ("beverage "); } } class Beer extends Beverage { public static void main{string [] args) { Beer b = new Beer (14) ; } public int Beer(int x) { this () ; System.out.print ("beerl") ; } public Beer() { System.out.print("beer2 "); } } 结果是什么?() ["beerl beverage","beer2 beverage","beverage beer2 beerl","编译失败"]
稳定质量是指通信网的可靠性,其指标有()。 ["失效率","平均故障间隔时间","BHCA","接通率","忙时话务量","平均修复时间"]
常作为医药文献检索工具的是() ["《中国药房杂志》","《中国药学文摘》","《中药大辞典》","《现代药物治疗学--临床药理与病理生理学基础》","《药名词典》"]
简述污染物在个体水平上的影响。