首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   442篇
  免费   13篇
  国内免费   3篇
财政金融   12篇
工业经济   52篇
计划管理   229篇
经济学   27篇
综合类   27篇
运输经济   2篇
旅游经济   4篇
贸易经济   76篇
农业经济   7篇
经济概况   22篇
  2023年   2篇
  2022年   4篇
  2021年   12篇
  2020年   15篇
  2019年   8篇
  2018年   7篇
  2017年   6篇
  2016年   3篇
  2015年   25篇
  2014年   40篇
  2013年   50篇
  2012年   60篇
  2011年   46篇
  2010年   33篇
  2009年   22篇
  2008年   27篇
  2007年   17篇
  2006年   22篇
  2005年   13篇
  2004年   18篇
  2003年   7篇
  2002年   5篇
  2001年   7篇
  2000年   3篇
  1999年   2篇
  1998年   1篇
  1997年   2篇
  1991年   1篇
排序方式: 共有458条查询结果,搜索用时 15 毫秒
1.
曹文 《价值工程》2021,40(3):155-157
针对富水砂层盾构接收易发生渗漏、涌砂、安全风险大等问题。在大量工程实践基础上,总结出以控制地下水为重点、坚持预防为主的施工理念,形成端头加固、止水帷幕、环箍注浆及止水装置的富水地层盾构接收技术,牢筑三道止水防线。技术成果在多项依托工程中成功应用,确保了该类地层盾构接收安全和风险可控。  相似文献   
2.
Based on the environmental psychology theory, this research conceptualizes and investigates the dimensions of e-servicescapes, and examines how each dimension influences fitness application and wearable device users’ emotions, satisfaction, and behavioral intention to continuously work out via the technology. This study employed three waves of surveys within the United States to collect data (N = 343), and conducted a path analysis to rigorously assess the proposed paths between identified constructs. The empirical findings revealed the significant determinants of negative emotion (i.e., usability, security, customization, entertainment value, interactivity, originality of design, relevance of information, and social factors) and positive emotion (i.e., usability, customization, entertainment value, interactivity, and relevance of information). Also, satisfaction was significantly impacted by both positive emotion and negative emotion, and behavioral intention was significantly influenced by positive emotion and satisfaction. Based on these findings, this study suggests theoretical (i.e., classification of the e-servicescape dimensionality and integration of the environmental psychology theory with the two-factor theory of motivation, focusing on a digital environment) and practical implications (i.e., ways to increase levels of consumer satisfaction with the technology and intention to continuously exercise with the technology) for scholars and practitioners in the fitness and mobile application/wearable device industries.  相似文献   
3.
在性能、成本和可靠性的多重约束下,采用商用货架(Commercial Off-The-Shelf,COTS)器件设计了一种高性能、低成本星载收发信机。该收发信机的硬件设计不但可同时满足星地和星间应用需要,而且还具有支持多波束、多信道接入的特点。软件设计主要解决了大多普勒频偏条件下的低信噪比解调和变长以太网数据帧的高效处理等问题。地面测试结果表明,在250 kb/s ~ 14 Mb/s信息速率范围内,误比特率低于1.0×10-6时所需的解调信噪比(Eb/N0)不超过2.8 dB,发射信号误差矢量幅度不超过1.9%,高速应用时处理时延可低至3.0 ms。为降低COTS收发信机的可靠性风险,分别在元器件、电路和系统层面进行了有针对性的可靠性保证措施。该设计经过了在轨测试的验证,对其他低轨商业通信载荷的研制有一定的参考价值。  相似文献   
4.
新能源汽车是未来汽车产业转型发展的重要方向。我国新能源汽车前期发展取得了突出的成绩,产销量位居世界首位。但目前产业发展正面临新形势,未来一段时期内将由“政策驱动”转向“政策+市场双驱动”。到2021年购置补贴完全退出后的后补贴时代,如何保障新能源汽车产业的健康、可持续发展,值得人们共同思考,开发什么类型的产品才能更好地满足消费者的需求,值得行业企业考虑。  相似文献   
5.
ABSTRACT

A smart speaker is a wireless device with artificial intelligence that can be activated through voice command. The artificial intelligence interacts in the form of a virtual personal assistant, such as Amazon’s “Alexa”. Companies are currently creating voice applications for smart speakers that allow consumers to use the personal assistant to perform tasks, such as acquiring information and ordering products. This is the dawn of a new type of interaction between brands and consumers, a new touchpoint. Brands need to catch the vision and create content for this new technology, content that is useful in the buying process. The purpose of this study is to determine what types of marketing messages people find acceptable on smart speakers. Based on the findings, a cognitive message strategy is effective with smart speakers. The paper presents three types of executional frameworks that are best suited for the design of a cognitive message: authoritative, testimonial, and slice-of-life. The overriding requirement for marketing on smart speakers is that the message must provide value to the listener.  相似文献   
6.
石璐珊  贾辉 《科技和产业》2020,20(3):108-115
产业集群能提高企业、区域和国家竞争力。当前以产业创新集群为代表的新一轮产业集群正在各地兴起。通过行业融合、知识外溢和集体行动,产业创新集群促进相关企业和支持性机构紧密互动而加速创新。医疗器械产业科技含量高,创新性强,是当前少数几个涉及学科最多的产业之一。以医疗器械产业为研究对象,从集群和区域创新发展的要义出发,挑选宁波地区的医疗器械行业,测算其行业集中度和产业集群效应,提出提升医疗器械行业集群度,激发产业创新集群活力的对策建议。  相似文献   
7.
The electronics industry is often regarded by scholars as an example of a sector driven by endless technological innovation and major competition between a few large companies, thus embodying the common view whereby the free market leads firms to innovate. On the other hand, some business historians have also emphasised that, since the beginning of the twentieth century, most of these companies were engaged in various international cartel agreements. The business and economic history literature on this industry reveals a clear-cut divide between the inter-war years and the post-war era. In this paper, however, we argue that technical and commercial cooperation between large electronics companies continued in various forms despite the spread of anti-trust policies after 1945. In this case study, we explore the global X-ray equipment industry from its beginnings around 1900 to the advent of the CT scanner in the early 1970s. The paper focuses on Siemens and Philips, the two largest manufacturers of radiological equipment. It demonstrates that both companies pursued their commercial and technical cooperation at least until the 1970s, although it was much less overt as during the interwar years.  相似文献   
8.
袁燕芬 《价值工程》2015,(15):144-146
本文针对以往双壁钢围堰下沉平面位置控制精度不高的难题,经方案比选,提出采用内岛式导向装置的想法,据此设计出一种控制围堰下沉过程中平面位置控制的内导向装置。并付诸实施。现以安徽省淮南孔李淮河大桥双壁钢围堰为例,论述该装置的工艺原理、构造形式及加工要点,通过实践有效解决了双壁钢围堰下沉过程中平面位置控制精度不高的施工难题,提高了双壁钢围堰的就位精度,取得了很好的经济效益和社会效益。为同类工程施工提供借鉴意义。  相似文献   
9.
The authors explored undergraduate business students’ feelings and thoughts about themselves, other students, and their professors when mobile devices are used in the lecture hall for nonacademic purposes. Specifically, they investigated mobile device use during class time, and whether students support it, are indifferent toward it, or consider it to be an intrusion. Using the critical incident technique, the authors thematically categorized students’ thoughts and feelings regarding mobile device usage in the classroom for nonacademic purposes. The results uncovered unique perspectives presented by the students that carry implications for students, professors and administrators.  相似文献   
10.
王文征 《价值工程》2014,(23):38-39
近几年来冶金起重机事故频发,特种设备监督检验机构对冶金起重机的检验显得尤为重要,本文针对其中的重要项——超速保护装置的检验方法进行了新的开拓。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号