ER9350电铲是巴润公司大型露天矿山连续开采的重要组成部分,针对ER9350电铲铲斗失效的4中形式,即斗唇断裂失效、铲斗底板开裂失效......

大猿叶虫Colaphellus bowringi Baly卵的颜色有浅黄色和深红色2种类型。调查卵的颜色与其后代滞育的发生和繁殖力的关系，结果表明，在......

目前关于人类性别在数量上大致均等的一般解释难以自圆其说.作者依据从进化论思想推导出的配偶供需量均等原则,不仅很好地解释了这......

The present study was performed to clarify the influence of having a firm purpose in life (PIL) on psychological and phy......

With the continuous improvement of the national economy and people's quality of life, people's attention to huma......