全文获取类型
收费全文 | 2633篇 |
免费 | 690篇 |
国内免费 | 97篇 |
出版年
2024年 | 3篇 |
2023年 | 22篇 |
2022年 | 28篇 |
2021年 | 28篇 |
2020年 | 51篇 |
2019年 | 44篇 |
2018年 | 42篇 |
2017年 | 101篇 |
2016年 | 142篇 |
2015年 | 81篇 |
2014年 | 231篇 |
2013年 | 208篇 |
2012年 | 192篇 |
2011年 | 209篇 |
2010年 | 186篇 |
2009年 | 226篇 |
2008年 | 167篇 |
2007年 | 201篇 |
2006年 | 211篇 |
2005年 | 209篇 |
2004年 | 169篇 |
2003年 | 155篇 |
2002年 | 91篇 |
2001年 | 86篇 |
2000年 | 43篇 |
1999年 | 58篇 |
1998年 | 47篇 |
1997年 | 36篇 |
1996年 | 27篇 |
1995年 | 23篇 |
1994年 | 21篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 17篇 |
1990年 | 22篇 |
1989年 | 10篇 |
1987年 | 1篇 |
排序方式: 共有3420条查询结果,搜索用时 15 毫秒
1.
2.
3.
Charles Streeper 《The Nonproliferation Review》2013,20(3):531-550
Radioactive sealed sources have a long history and a much wider worldwide distribution than do weapons-usable fissile materials. This article compares the mechanisms for controlling radioactive sources with those of weapons-usable materials and makes the case for improved policy making on the safe and secure management of radioactive sources (often referred to simply as “sources”). Such sources have been widely distributed with commercial and government support to nearly every country, yet there are no legally binding, international agreements or regulations to control any aspect of their life cycle. This is problematic because some sources that are disused, abandoned, or otherwise fall out of regulatory control could be used in the form of a radiological dispersal device (RDD, or dirty bomb). An RDD could pose significant economic and psychological impacts with the potential for detrimental effects on public health. The lack of international measures to control sources is troubling for several reasons: creating an RDD is much easier than fashioning a nuclear weapon from scratch or from stolen fissile materials; given the many incidents involving diversion from regulatory control and the misuse of sources, an RDD attack would be one of the more likely scenarios; materials security for sources is generally weak and inconsistent; it is nearly impossible to determine the total amount of sources manufactured and distributed; used sources are frequently found uncontrolled and transiting borders, and penalties are light at best; the market-based supply and demand of sources facilitates their rapid and loosely regulated distribution; and the “peaceful uses” aspect of the Treaty on the Non-Proliferation of Nuclear Weapons along with norms that began developing around the time of Atoms for Peace have promoted the nearly unchecked global distribution of sources. Several immediate and long-term actions are suggested to reduce the threat posed by radiological sources. 相似文献
4.
ABSTRACTNuclear disarmament is often seen as eventually requiring access to nuclear warheads or to the warhead-dismantlement process to verify that a state has not hidden weapons or weapon-materials despite promising to disarm. This article suggests this view is misplaced, and that what is needed is a verification mechanism able to provide reliable assurances of the absence of fissile materials available for use in weapons after a state has disarmed. Such a mechanism will need an initial declaration of the amount of fissile materials held by a state for all purposes, military and civilian. In a state with a nuclear arsenal awaiting elimination, this declaration would have to include materials that may not be available for verification because they are in nuclear weapons or are in other classified or proliferation-sensitive forms. This article describes a verification arrangement that does not require access to materials in weapons and in sensitive forms while still allowing checks on the overall accuracy of the declaration. Verification of the completeness and correctness of the declaration is deferred to the time when the weapons-relevant material enters the disposition process, at which point it no longer has any sensitive attributes. By removing the focus on monitoring warheads and dismantlement, this new approach could provide a more manageable path to nuclear disarmament. 相似文献
5.
分析了战时装备调配保障决策的特点,运用模糊聚类分析法对装备调配保障对象进行了分组和优先级排序,以此为基础,运用目标规划法构建了战时装备调配保障决策模型,最后,通过实例验证了模型的可行性和有效性. 相似文献
6.
摘要:针对单小批量武器装备保障的特殊需求,对传统的质量屋模型进行了改进,建立了基于装备保障需求与保障规则的质量屋模型,利用整数规划技术进行求解,使得单小批量武器的装备保障规则按照实际保障需求重新排列优先次序,并通过对某型火炮保障方案的筛选验证了模型的正确性.新的质量屋模型发展完善了质量屋的理论与方法,有助于提高单小批量武器的装备保障能力. 相似文献
7.
试验研究了穿甲子弹垂直侵彻高强防弹钢的机理,提出了一个分析靶板极限速度和弹体剩余速度的理论模型,该模型综合考虑了材料的应变率与热软化效应,结果表明,理论值与试验值吻合很好.分析了失效准则的影响,研究了剪切带温度和靶板耗能随入射速度的变化规律. 相似文献
8.
9.
10.
一种面向故障的软件测试新方法 总被引:14,自引:0,他引:14
宫云战 《装甲兵工程学院学报》2004,18(1):21-25
面向故障的软件测试方法是今后软件测试技术研究的主要内容.和传统的面向整个软件的测试方法相比,面向故障的测试方法对故障的检测针对性更强,特别是对传统测试方法难以检测的故障如存储器泄露故障、数组越界故障、空指针引用故障等的检测是非常有效的.从方法学上讲,面向故障的测试方法标志着一个测试理论的成熟,在测试方法学中具有里程碑的意义.面向故障测试方法有2个问题需要解决:①软件的故障模型,②面向该模型的自动测试方法,此文重点论述软件的故障模型问题. 相似文献