全文获取类型
收费全文 | 678篇 |
免费 | 68篇 |
国内免费 | 34篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2021年 | 14篇 |
2020年 | 7篇 |
2019年 | 29篇 |
2018年 | 29篇 |
2017年 | 34篇 |
2016年 | 38篇 |
2015年 | 25篇 |
2014年 | 56篇 |
2013年 | 104篇 |
2012年 | 18篇 |
2011年 | 38篇 |
2010年 | 39篇 |
2009年 | 44篇 |
2008年 | 44篇 |
2007年 | 35篇 |
2006年 | 38篇 |
2005年 | 32篇 |
2004年 | 39篇 |
2003年 | 29篇 |
2002年 | 10篇 |
2001年 | 16篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 3篇 |
排序方式: 共有780条查询结果,搜索用时 312 毫秒
101.
开放式自动测试系统软件设计 总被引:3,自引:0,他引:3
实现测试程序的可移植性、改善测试系统仪器互换性和提高ATS新技术注入能力是通用ATS研制的热点问题,遵循标准和实现开放式系统是解决问题的途径,软件系统是当前通用ATS实现开放性的制约因素.根据领域需求软件采用层体系结构模式,合理划分各层功能,在高层提供面向信号的编程接口,资源控制层提供了面向功能的接口,资源管理实现了系统对资源控制层构件开放的动态集成方式,实现了开放式的系统软件构架. 相似文献
102.
103.
为解决多学科设计优化方法中多学科设计、多学科分析、多学科优化过程与卫星总体设计流程集成的问题,采用变复杂度建模技术,并借鉴产品数据管理思想,设计并实现了面向总体设计的卫星集成设计软件系统。阐述了软件的设计思想、系统组成和功能特点,并给出了月球探测卫星概念设计问题的具体应用实例,结果表明软件在解决多学科设计优化方法应用于卫星集成设计问题时的可行性。 相似文献
104.
105.
106.
水声信息流仿真软件系统涉及多目标、多声纳以及多变的海洋环境.仿真软件的复用性是现代软件工程的重要性能指标.针对系统开放性的特点,在领域分析模型的基础上,采用了面向对象方法设计仿真软件模型.为了满足软件多层次复用的需求,应用软件架构技术和设计模式设计仿真软件.根据水声信息流仿真软件需求,系统划分为四层结构;按功能,层又可分解为包.可复用的设计模式用于设计不同层和包中类之间的关系.提出的仿真软件模型具有良好的可扩充性与可复用性. 相似文献
107.
设计安全策略模型时应考虑安全策略的时序特性和灰色特性,还应综合考虑保密性、完整性和可用性三方面的需求。已有的安全模型没有描述时序性和灰色特性,而且一般只侧重描述保密性或完整性。为此,本文提出了动态灰色时序系统(简称DGTS)。本文详细描述了DGTS,以及基于DGTS的动态语义设计的灰色时序安全策略规范语言GTSL。 相似文献
108.
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
109.
Elling N. Tjønneland 《African Security Review》2013,22(3):190-196
SADC has a poor record in advancing peace and security in Southern Africa. Many identify poor policy frameworks and weak technical capacities as the major obstacles. Laurie Nathan goes beyond these easy explanations in his important new book on SADC. Absence of common democratic values and reluctance to surrender state sovereignty are key factors preventing SADC from making progress according to this book. This article argues that Nathan overstates the case and that there are real prospects and potentials for making further progress in regional cooperation. The lessons from the history of European integration also points to the important role of regional leadership. South Africa, in coalition with other likeminded countries, may still be in a position to move the SADC project forward. 相似文献
110.
Şebnem Udum 《The Nonproliferation Review》2013,20(2):365-377
As worries have grown about global warming and the sustainability and price of fossil fuels, the demand for nuclear energy has increased, and nuclear power is increasingly viewed as a reliable and clean resource. However, the so-called nuclear renaissance coincides with an international security environment in which the norms of nuclear nonproliferation seem to be eroding. Turkey, a non-nuclear weapon state, plans to generate nuclear power to meet future energy demands, but it is aware of and concerned with regional proliferation trends. Questions have also been raised regarding Ankara's rationale for using nuclear energy, as well as its potential motivations and capabilities regarding future proliferation. This article will provide an overview of Turkey's nuclear energy history and plans, as well as the proliferation-related questions that could arise; it will also look at the domestic debate on nuclear energy and Turkey's status as a non-nuclear weapon state. 相似文献