全文获取类型
收费全文 | 760篇 |
免费 | 0篇 |
专业分类
760篇 |
出版年
2021年 | 11篇 |
2019年 | 15篇 |
2018年 | 8篇 |
2017年 | 19篇 |
2016年 | 13篇 |
2015年 | 14篇 |
2014年 | 18篇 |
2013年 | 134篇 |
2012年 | 7篇 |
2010年 | 10篇 |
2009年 | 17篇 |
2007年 | 11篇 |
2006年 | 10篇 |
2005年 | 11篇 |
2004年 | 16篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 7篇 |
1998年 | 15篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 16篇 |
1992年 | 11篇 |
1991年 | 18篇 |
1990年 | 12篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 20篇 |
1986年 | 20篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 7篇 |
1979年 | 11篇 |
1978年 | 15篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 11篇 |
1972年 | 11篇 |
1971年 | 6篇 |
1970年 | 11篇 |
1969年 | 8篇 |
1967年 | 6篇 |
排序方式: 共有760条查询结果,搜索用时 15 毫秒
221.
222.
223.
224.
The main objective of the paper is to decipher the military expenditure–economic growth relationship, taking the level of economic development (income) into consideration. Our findings suggest the following: (i) military expenditure has a significantly negative relationship to economic growth for the 23 countries with initial incomes (threshold variable) less than or equal to $475.93; (ii) when the threat level is heightened, economic growth (23 countries) is expected to decrease. However, military expenditure in the presence of sufficiently large threats increases growth; (iii) for the remaining 69 countries whose initial incomes (real GDP per capita in 1992 price) exceed $475.93, no significant relationship exists whether the threat variable is taken into consideration or not. 相似文献
225.
This paper explores some of the key issues associated with the restructuring of the defence industry. A comparison is made between the US and the European Defence Industrial Bases in terms of the drivers for change and the paradigms within which change has taken place. Having shown that some very important differences exist, the paper then explores the approaches that have been adopted for industry consolidation and references them to the academic literature on mergers and acquisitions (M&As) and strategic alliances (SAs). Given that most of the key defence players recognise the need to be global players, the paper presents an argument that the European firms’ experience of operating with a wide range of forms of corporate alliance will serve them in good stead for operating on a global defence scale. US firms, in contrast, have focused largely on M&A activity. 相似文献
226.
Richard B. Streeter Guy W. Hagen Edward E. Patenaude Dennis K. Killinger 《Defence and Peace Economics》2013,24(6):569-587
This paper presents a model for converting legacy defense production facilities into private‐sector economic resources. Specifically, this paper will examine as a case study the first successful conversion of a former U.S. Department of Energy nuclear weapons production installation, including reasons for its success, its costs and benefits, and lessons for public policy. It is envisioned that this model may be useful for mitigating local economic hardship resulting from defense “downsizing” and for privatizing production capacities critical for national defense. 相似文献
227.
228.
超精密铣削的三维微加工工艺 总被引:1,自引:0,他引:1
本研究旨在对用于获取有雕刻表面金属工件的超精密微加工工艺进行探讨。研究中使用的是车床型的超精密铣床,由分辨率为1nm的X和Z向运动工作台及分辨率为0.0001度的可定位的C轴组成。作为一种铣削工具,一种改进型的由一颗水晶钻构成的“仿球尖铣刀”被放置在X轴的高速气浮轴承之上。这样一来,X轴和C轴的协调运动就可产生三维铣削的效果。为提高表面粗糙度,通过模拟我们研究的刀具边沿和工件表面的接触情况,结果发现,刀具低速进给时切削比较有效。作为三维微加工工艺的一个例子,运用数字仪提供的扫描数据在一个直径为3mm的铜表面上制作一个传统的NOH面罩。经证明,超精密铣床有潜力加工出表面粗糙度为69nm(P—V值)的工件。 相似文献
229.
The problem of determining the sample sizes in various strata when several characteristics are under study is formulated as a nonlinear multistage decision problem. Dynamic programming is used to obtain an integer solution to the problem. © 1997 John Wiley & Sons, Inc. 相似文献
230.
This article deals with the problem of scheduling jobs with random processing times on single machine in order to minimize the expected variance of job completion times. Sufficient conditions for the existence of V-shaped optimal sequences are derived separately for general and ordered job processing times. It is shown that when coefficient of variation of random processing times are bounded by a certain value, an optimal sequence is V-shaped. © 1997 John Wiley & Sons, Inc. 相似文献