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   72篇
  免费   3篇
  2021年   1篇
  2020年   1篇
  2019年   10篇
  2018年   9篇
  2017年   3篇
  2016年   4篇
  2015年   3篇
  2014年   2篇
  2013年   29篇
  2012年   1篇
  2010年   2篇
  2009年   1篇
  2008年   2篇
  2007年   2篇
  2004年   1篇
  2002年   1篇
  1996年   3篇
排序方式: 共有75条查询结果,搜索用时 23 毫秒
31.
This article assesses the existing literature on logistics in war, concluding that there is no satisfactory conceptual definition of logistics. It proposes a concept of logistics derived from Clausewitz's theory of war to fill that void. This is presented as a derivation because Clausewitz's distinction between (1) the use of the fighting forces (tactics and strategy) and (2) all other activities in war that were required so that forces could be taken as a given. The latter, left unnamed by Clausewitz, corresponds to a concept of logistics that proves to be an analytical peer to Clausewitz's categories of politics, tactics and strategy.  相似文献   
32.
There have been growing claims in media circles and law-enforcement settings that street gangs and criminal groups are turning to Internet-based social networking sites for various reasons ranging from the showcasing of their images and exploits to the suspected recruitment of members. The present study investigates whether such a trend is, in fact, in place. The presence of street gangs on these Internet sites is referred to as cyberbanging. While there is some anecdotal evidence suggesting that gangs are turning to social networking sites, there is little available research on exactly how street gangs and criminal groups use the Internet. Our main argument is that gang culture is in many ways an individualized phenomenon and this feature ties in directly with recent assessments of the Internet as a setting that is governed by a process of networked individualism. This theoretical link between the individualized gang setting and the presence of gang members on social networking sites helps us understand why recruitment is improbable even in a context where people are openly diffusing their image and exploits to a growing number of Internet users. The empirical segment of this research adds to this general outlook. Based on a keyword search of over 50 street gang names, the three main social networking sites (Twitter, Facebook, and MySpace) were monitored for street gang presence. Results illustrate that gang presence on social networking sites is linked primarily to promoting a general gang or street culture through individual displays. In regard to the visitors to such sites, there is no evidence that they are being tricked or manipulated in any way. They are, however, showing their curiosity in regard to such groups and, for those who share their comments and opinions, signs of support are evident. Thus, whereas criminal gangs are not proactively using the Internet to convert anyone into being gang members, social networking sites are creating a new venue for people who share or are sensitive to the values underlying street gang lifestyle to come together. These sites essentially create a new convergence setting for gang members to interact with a wider number of people who would probably never have been exposed to their lifestyles and exploits through physical interactions. The study's conclusion extends these findings toward further research in this area, as well as outlining the more relevant implications for law-enforcement monitoring of this growing phenomenon.  相似文献   
33.
This paper models the determination of the defence industrial base – the number of different military systems a country decides to maintain. High R&D costs means that few countries can afford to produce major weapons systems and the producers also import systems. Non‐producers rely on imports and we assume their demand is driven by regional arms races. Military capability is determined by the number of systems and the quantity and quality of each. We examine how the defence industrial base is influenced by military expenditures, R&D costs, export controls, the nature of regional arms races and a variety of other factors.  相似文献   
34.
Uruguay is a country with a very unusual profile, since it has just 3.4 million inhabitants but is among the top ten troop contributors to the UN PKO (Peace Keeping Operations) and is the first contributor per capita. In 2002 and 2003 it was the seventh troop contributor to the UN, and by the end of 2005 it was eighth in the UN ranking. Uruguay has never had any imminent external threat to its security after its independence in 1828, and it has had no internal threat since the end of the urban guerrillas’ actions in the 1970s. The country has no defence industry, and has always had an all‐volunteer military service, which presently involves almost 1% of the total population, and about 2% of the labour force. The empirical evidence presented in this paper shows that, in the past decades, Uruguayan defence spending has been influenced mainly by internal factors, most of them of an economic nature. The high participation in PKO has not increased military expenditure and it has produced a positive impact on the country’s economy.  相似文献   
35.
The traditional view of the defence industry obtaining large profits from contracts with the Ministry of Defence relies on several assumptions. Among these are the use of such arrangements as an instrument of industrial policy, the strong market power enjoyed by prime contractors, and the inefficiency encouraged by the sector. The findings show that defence contracts have a positive effect on profits, as well as the prizes for innovation and the market power enjoyed by some defence subsectors.  相似文献   
36.
We look at the different ways of aggregating the exports of dual use products to give the security perception of exporter countries and their consistency with the relevant export control regimes. Also, we analyze different models of export controls highlighting the role of the perception of security, market structure and competition between exporting firms in determining the existence of multiple equilibria and therefore, the need for coordination between countries in setting export controls.  相似文献   
37.
38.
空间飞行器主动段的轨道估计与误差分析   总被引:1,自引:0,他引:1  
为了对无源探测卫星系统的定轨方式和精度进行定量分析,通过坐标转换、受力分析、拟合、最小二乘法、微分方程数值解法与误差分析等方法,建立了基于卫星无源探测的空间飞行器在主动段的交汇定位优化模型和运动方程模型。基于模拟数据和模型,给出了卫星和空间飞行器的轨道曲线以及卫星的系统误差。经过系统误差修正,空间飞行器的估计轨道误差仅为7.582 1 m。  相似文献   
39.
The dielectric constant (DC) is one of the key properties for detection of threat materials such as Improvised Explosive Devices (IEDs). In the present paper, the density functional theory (DFT) as well as ab-initio approaches are used to explore effective methods to predict dielectric constants of a series of 12 energetic materials (EMs) for which experimental data needed to experimentally determine the dielectric constant (refractive indices) are available. These include military grades energetic materials, nitro and peroxide compounds, and the widely used nitroglycerin. Ab-initio and DFT calculations are conducted. In order to calculate dielectric constant values of materials, potential DFT functional combined with basis sets are considered for testing. Accuracy of the calculations are compared to experimental data listed in the scientific literature, and time required for calculations are both evaluated and discussed. The best functional/basis set combinations among those tested are CAM-B3LYP and AUG-cc-pVDZm, which provide great results, with accuracy deviations below 5% when calculated results are compared to experimental data.  相似文献   
40.
在综述消防责任事故罪中的"经消防监督机构通知采取改正措施拒绝执行"要件观点的基础上,对该要件的存在基础、对主体范围的限制、放纵犯罪以及刑法的预防功能等方面进行了分析,指出该要件的缺陷,进而提出合理化建议。  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