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   640篇
  免费   21篇
  国内免费   1篇
  662篇
  2025年   1篇
  2024年   4篇
  2023年   14篇
  2022年   5篇
  2021年   5篇
  2020年   6篇
  2019年   23篇
  2018年   16篇
  2017年   26篇
  2016年   24篇
  2015年   24篇
  2014年   42篇
  2013年   134篇
  2012年   37篇
  2011年   28篇
  2010年   24篇
  2009年   26篇
  2008年   17篇
  2007年   14篇
  2006年   19篇
  2005年   24篇
  2004年   25篇
  2003年   18篇
  2002年   19篇
  2001年   23篇
  2000年   14篇
  1999年   8篇
  1998年   13篇
  1997年   4篇
  1996年   3篇
  1995年   7篇
  1994年   3篇
  1992年   6篇
  1991年   3篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
排序方式: 共有662条查询结果,搜索用时 0 毫秒
591.
Nuclear optimists and pessimists disagree on whether the odds of nuclear war are low or high. This viewpoint assesses the odds of nuclear war over the past sixty-six years, exploring three pathways to nuclear war: an international crisis leading directly to nuclear war, an accident or misperception leading to nuclear escalation or nuclear retaliation against an imaginary attack, and a general conventional war leading to nuclear war. The assessment is based on the application of Bayes's theorem and other statistical reasoning and finds that the expected probability of nuclear war during this historical period was greater than 50 percent. This level of risk is unacceptably high. It is therefore urgent that effective measures be taken to substantially reduce the risk of nuclear war.  相似文献   
592.
The prospect of the United States continuing to reduce the size of its nuclear arsenal to “very low numbers” has raised questions in Japan and South Korea, where US extended deterrence guarantees are premised on the “nuclear umbrella.” In both countries, however, concerns focus less on numerical arsenal size than on the sufficiency of specific nuclear and non-nuclear capabilities to meet evolving threats and on the degree of broader US commitment to these alliances. This article assesses developments in US-Japan and US-South Korea relationships in response to the Obama administration's nuclear disarmament policies, focusing on how the evolutionary course of those relationships may in turn condition prospects for sustaining this US nuclear policy direction. The analysis finds that the challenges of deterrence credibility and allied reassurance are difficult and long-term, but also that US nuclear arsenal size is secondary to broader political, strategic, and military factors in meeting these challenges. The evaluation concludes that strong alliance relationships and strategic stability in East Asia can be maintained while the size of the US nuclear arsenal continues to decline, but also that deterioration of these relationships could imperil core US nuclear policy and nonproliferation objectives.  相似文献   
593.
Fusion reactors have the potential to be used for military purposes. This article provides quantitative estimates about weapon-relevant materials produced in future commercial fusion reactors and discusses how suitable such materials are for use in nuclear weapons. Whether states will consider such use in the future will depend on specific regulatory, political, economic, and technical boundary conditions. Based on expert interviews and the political science literature, we identify three of these conditions that could determine whether fusion power will have a military dimension in the second half of this century: first, the technological trajectory of global energy policies; second, the management of a peaceful power transition between rising and declining powers; and third, the overall acceptance of the nuclear normative order. Finally, the article discusses a few regulatory options that could be implemented by the time fusion reactors reach technological maturity and become commercially available; such research on fusion reactor safeguards should start as early as possible and accompany the current research on experimental fusion reactors.  相似文献   
594.
An increasing number of countries recognize the special risks of nuclear terrorism associated with the civilian use and storage of and commerce in highly enriched uranium (HEU). They are especially concerned that non-state actors might gain access to HEU and use it to build and detonate improvised nuclear devices. The risk is aggravated by the very large global stocks of HEU, some of which are inadequately protected. Although HEU has few commercial uses, and most experts believe it is technically feasible to substitute low-enriched uranium for HEU in nearly all civilian applications, efforts to reduce HEU stocks have been impeded by a variety of economic, political, and strategic considerations. This article analyzes the nature of these impediments and discusses what is required to overcome them.  相似文献   
595.
Based on the first-person account of coauthor Pierre Billaud, a prominent French participant, this article describes for the first time in such detail the history of the development of the French hydrogen bomb in the 1960s and the organization of military nuclear research in France. The authors illustrate the extent to which French defense and governmental authorities did not support research on thermonuclear weapons until 1966. Billaud, a project insider, relates the historical episodes that led to France's successful 1968 thermonuclear test, including the names of the individuals involved and how a timely tip from a foreign source hastened the success of the first H-bomb test.  相似文献   
596.
THE NPT     
This article assesses the successes and failures of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) since its creation in 1968 by developing and applying a set of “metrics” to each of the NPT's substantive articles as well as to its withdrawal provisions. In light of this analysis, the article also puts forward some specific proposals for strengthening the NPT and its implementation, with a view to the debate and decisions at the upcoming 2010 NPT Review Conference. A concluding section turns explicitly to the 2010 NPT Review Conference and proposes pursuit of agreement on three NPT Action Plans: one for nonproliferation, one for peaceful uses, and one for nuclear disarmament. Combining vision and practicable steps, these Action Plans would set out a roadmap for action between the 2010 and the 2015 NPT Review Conferences. They could provide a foundation for substantive exchanges—in this case, on progress toward their implementation—during the preparations for the 2015 conference.  相似文献   
597.
“Nuclear threshold states”—those that have chosen nuclear restraint despite having significant nuclear capabilities—seem like the perfect partners for the reinvigorated drive toward global nuclear disarmament. Having chosen nuclear restraint, threshold states may embrace disarmament as a way to guarantee the viability of their choice (which may be impossible in a proliferating world). Supporting disarmament efforts affirms their restraint, both self-congratulating and self-fulfilling. Additionally, the commitment to their non-nuclear status springs at least in part from a moral stance against nuclear weapons that lends itself to energetic support of global disarmament. However, threshold states also offer significant challenges to the movement for nuclear weapons elimination, in particular in relation to acquisition of enrichment and reprocessing facilities. This article analyzes both the challenges and opportunities posed by threshold states by examining the cases of Brazil and Japan.  相似文献   
598.
Reagan's Secret War: The Untold Story of His Fight to Save the World from Nuclear Disaster, by Martin Anderson and Annelise Anderson. Crown Publishers, 2009. 464 pages, $32.50.

The Rebellion of Ronald Reagan: A History of the End of the Cold War, by James Mann. Viking, 2009. 410 pages, $27.95.  相似文献   
599.
思想政治工作是我党我军的政治优势 ,是团结全党和全国各族人民实现党和国家各项任务的中心环节。面对新的形势 ,新的特点 ,如何使思想政治工作更具有实效性 ,是部队思想政治工作面临的重大理论问题和现实问题。  相似文献   
600.
基于小波变换与FFT算法的电能质量信号分析   总被引:8,自引:3,他引:8  
提出了一种基于小波变换和FFT相结合分析电能质量信号的方法.用小波变换检测电能质量信号的间断点,对由间断点分段得到的信号用FFT进行频谱分析,并进行了计算机仿真,取得了较满意的结果.  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