全文获取类型
收费全文 | 224篇 |
免费 | 150篇 |
国内免费 | 12篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 18篇 |
2016年 | 16篇 |
2015年 | 10篇 |
2014年 | 23篇 |
2013年 | 18篇 |
2012年 | 10篇 |
2011年 | 19篇 |
2010年 | 16篇 |
2009年 | 20篇 |
2008年 | 21篇 |
2007年 | 20篇 |
2006年 | 21篇 |
2005年 | 22篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 6篇 |
2001年 | 10篇 |
2000年 | 16篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1987年 | 1篇 |
排序方式: 共有386条查询结果,搜索用时 546 毫秒
61.
为了准确刻画对象模型,采用一阶等效电路瞬态涡流分析法对动态边端效应影响下动初级高速六相直线感应电机的参数时变规律进行了定量计算,并通过感应涡流损耗推导得到考虑动态边端效应时电机的等效电路。基于此,通过电磁推力计算及效率评估对动态边端效应影响下电机的工作特性进行了详细分析。利用不同运行速度条件下的有限元仿真及动态实验验证了理论分析和推导的正确性。 相似文献
62.
讨论作业具有线性加工时间,作业间具有链约束的两台处理机流水作业排序问题,目标函数为极小化完工时间。在作业加工时间简单线性恶化下,提出作业的非负开始和停止延迟恶化率,构造了满足约束条件的复合作业。在此基础上,给出作业间具有平行链约束的两台处理机流水作业排序问题的最优多项式算法。 相似文献
63.
64.
侯谦民 《海军工程大学学报》2006,18(1):24-26
借助Z上矩阵A∈Mm×n(Z)的标准形式D=VAU=diag(d1,d2,…,dq,0,…,0),得到了整环上不定方程组AX=B的通解公式以及矩阵初等变换法. 相似文献
65.
This article outlines the widespread needs of South African military veterans and the possible consequences if the promises made in the recent Military Veterans Act are not met. The first part of the article defines who generally qualifies as a military veteran, how they are typically compensated in various countries with specific reference to neighbouring southern African countries, and what the consequences are when veterans become disenchanted with the state. The second part focuses on South Africa and the recent debates on military veterans and their entitlements. With reference to the findings of a qualitative study conducted among military veterans, parliamentary debates and media reports, an assessment is made of the demands and affordability of promised benefits and the consequences should the state not deliver. The conclusion is reached that heightened expectations are presently frustrated by slow roll-outs, and this is likely to increase the possibility of protest action. This has now the potential to create further tension within the ruling party and civil society, as the pressure on public finances mounts and demands become unsustainable. The effect this may have on political stability will depend on how the government manages this issue. 相似文献
66.
Stella Karagianni 《Defence and Peace Economics》2013,24(2):139-148
This paper uses linear and non‐linear Granger causality methods to determine the causal relationship between defense spending and economic growth in Turkey for the period 1949–2004. The innovative feature of this paper is that it provides evidence regarding the nonlinear causal dependence between military spending and economic growth in Turkey. The empirical results contribute to the empirical literature by indicating support for both linear and non‐linear causality between military expenditures and economic development and they may prove useful in theoretical and empirical research by regulators and policy makers. 相似文献
67.
摘要:研究一类具有leakage时滞的离散型神经网络的状态估计问题.通过构造新的Lyapunov泛函得到保证估计误差全局渐近稳定的充分条件,并通过求解一个线性矩阵不等式(LMI)得到状态估计器的增益矩阵.采用一种新的时滞分割方法将变时滞区间分割为多个子区间,使该结果在获得更小的保守性同时也降低了计算的复杂度. 相似文献
68.
机动飞行条件下,运动误差的幅度较大,频域运动补偿精度难以满足机载超宽带合成孔径雷达(UWB SAR)高精度成像的要求,需要采用精确的时域后向投影(Back Projection,BP)算法,然而原始BP算法的巨大计算量限制了其实际应用。提出了一种基于子图像快速因式分解BP(Sub-image Fast Factorized BackProjection,SIFFBP)算法的机动飞行条件下机载UWB SAR成像方案,并对其子孔径和子图像划分的约束关系进行了推导,给出了算法步骤,并分析了算法的计算量。仿真和实测数据处理结果表明,SIFFBP算法能够在保证处理精度的同时,大幅度提高处理效率,非常适合于机动飞行条件下的机载UWB SAR成像处理。 相似文献
69.
以BLUE算法和GDOP为基本定位算法和精度分析工具,评估多基地雷达的定位性能,建立以GDOP最小值最小和有效监控区最大为目标的多基地雷达布站优化模型.仿真结果表明,通过以下措施可提高定位性能:①增加收发站总数;②采取扇形方式布站;③优先增加部署接收站;④交替部署收发站;⑤通过优化模型优化扇形布站分布角总和. 相似文献
70.
A critical element in implementing a compensation scheme including nonmonetary incentives (NMIs) is recognizing that preferences vary widely across Service members. There are at least three sources of variability: across different population classes, across individuals within a population class, and across NMI packages for a particular individual. Surveys across different military communities, ranks, and years of Service show the difficulty of identifying any NMI that has significant value for even 50% of the active duty force. At the same time, approximately 80% of the surveyed Service members expressed a significant positive value for at least one NMI. Therefore, one-size-fits-all incentive packages will not be nearly as effective as more personalized incentive packages. The authors discuss variability in Service member NMI preferences and outline an approach to implementing personalized NMI packages in military compensation through a sealed-bid reverse auction, where Service members select individual NMIs from a “cafeteria-style” menu of options. 相似文献