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   388篇
  免费   6篇
  2021年   7篇
  2019年   7篇
  2018年   5篇
  2017年   3篇
  2016年   7篇
  2014年   5篇
  2013年   63篇
  2012年   3篇
  2009年   4篇
  2008年   2篇
  2007年   13篇
  2005年   2篇
  2004年   3篇
  2003年   7篇
  2002年   6篇
  2001年   3篇
  2000年   3篇
  1999年   4篇
  1998年   7篇
  1997年   8篇
  1996年   9篇
  1995年   3篇
  1994年   6篇
  1993年   10篇
  1992年   8篇
  1991年   9篇
  1990年   13篇
  1989年   17篇
  1988年   14篇
  1987年   7篇
  1986年   14篇
  1985年   8篇
  1984年   4篇
  1983年   3篇
  1982年   10篇
  1981年   6篇
  1980年   7篇
  1979年   9篇
  1978年   8篇
  1977年   5篇
  1976年   5篇
  1975年   5篇
  1974年   8篇
  1973年   5篇
  1972年   3篇
  1971年   7篇
  1970年   6篇
  1969年   5篇
  1967年   5篇
  1948年   4篇
排序方式: 共有394条查询结果,搜索用时 31 毫秒
241.
This article argues that an increasingly sea-power-minded China will neither shelter passively in coastal waters, nor throw itself into competition with the United States in the Pacific Ocean. Rather, Beijing will direct its energies toward South and Southeast Asia, where supplies of oil, natural gas, and other commodities critical to China's economic development must pass. There China will encounter an equally sea-power-minded India that enjoys marked geostrategic advantages. Beijing will likely content itself with ‘soft power’ diplomacy in these regions until it can settle the dispute with Taiwan, freeing up resources for maritime endeavors farther from China's coasts.  相似文献   
242.
243.
244.
A UK House of Commons Defence Committee (HCDC) Report on the Gulf War recommended that the UK should be self‐sufficient in supporting its Armed Forces in times of crisis and not even rely on its Allies. This recommendation is at odds with UK Government policy which rejects any formal strategy of support for the defence industrial base preferring international open competition as its procurement philosophy. This paper examines the various factors ranging from the supply of raw materials, production capacity, stockpiling, international joint ventures, and competition through to the effects on the technological update of weapon systems resulting from this philosophy. It draws conclusions supporting the HCDC recommendation and calls for joint MOD‐Industry action to address the issues involved and thereby reduce the risks to the Defence of the Realm.  相似文献   
245.
A plethora of arguments from the ‘public choice school’ suggest that public goods are ‘under‐supplied’ by comparison with public sector provision of more private goods. The implication is that rent seeking by the ‘military‐industrial complex’ serves, in some measure, to offset potential allocative inefficiency. In this paper a comparison of rent seeking by producers of public goods and producers of private goods identifies a bias that favours public good supply. The bias results from the different way in which collective demand for public goods and for private goods is expressed. The prospect of larger rents to the ‘military‐industrial complex’ implies greater rent‐seeking expenditures in this sector. The extent to which public goods (and, in particular, defence) are ‘under supplied’ is much exaggerated.  相似文献   
246.
Becoming a nuclear weapon state and sustaining a militarily credible nuclear weapons capability is far from trivial, especially for medium powers. Such a capability is demonstrated by much more than firing a first test or acquiring significant quantities of fissile material; capability is indicated by factors including weaponization, delivery of weapons, reliability and effectiveness of weapons and their delivery systems, fissile material availability, and nuclear and non-nuclear testing. Files in the British National Archives shed considerable light on the problems faced by the nuclear weapon program of the United Kingdom from 1952 through the late 1960s. The question is whether this experience is unique or if it instead offers insights into the potential problems faced by, or facing, other medium or aspiring nuclear weapon states. The proliferation-related topics highlighted include: fissile material production, nuclear testing, the first weapon, weapon delivery rates, non-nuclear testing, delivery platform problems, and long-term maintenance and capability sustainability. Further research could provide clearer insights.  相似文献   
247.
Consider an experiment in which only record-breaking values (e.g., values smaller than all previous ones) are observed. The data available may be represented as X1,K1,X2,K2, …, where X1,X2, … are successive minima and K1,K2, … are the numbers of trials needed to obtain new records. We treat the problem of estimating the mean of an underlying exponential distribution, and we consider both fixed sample size problems and inverse sampling schemes. Under inverse sampling, we demonstrate certain global optimality properties of an estimator based on the “total time on test” statistic. Under random sampling, it is shown than an analogous estimator is consistent, but can be improved for any fixed sample size.  相似文献   
248.
Moment estimators for the parameters of the Weibull distribution are considered in the context of analysis of field data. The data available are aggregated, with individual failure times not recorded. In this case, the complexity of the likelihood function argues against the use of maximum-likelihood estimation, particularly for relatively large sets of data, and moment estimators are a reasonable alternative. In this article, we derive the asymptotic covariance matrix of the moment estimators, and provide listings for BASIC computer programs which generate tables useful for calculation of the estimates as well as for estimating the asymptotic covariance matrix using aggregated data.  相似文献   
249.
Minimum cardinality set covering problems (MCSCP) tend to be more difficult to solve than weighted set covering problems because the cost or weight associated with each variable is the same. Since MCSCP is NP-complete, large problem instances are commonly solved using some form of a greedy heuristic. In this paper hybrid algorithms are developed and tested against two common forms of the greedy heuristic. Although all the algorithms tested have the same worst case bounds provided by Ho [7], empirical results for 60 large randomly generated problems indicate that one algorithm performed better than the others.  相似文献   
250.
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