全文获取类型
收费全文 | 114633篇 |
免费 | 14184篇 |
国内免费 | 10163篇 |
学科分类
工业技术 | 138980篇 |
出版年
2024年 | 869篇 |
2023年 | 2249篇 |
2022年 | 4303篇 |
2021年 | 4681篇 |
2020年 | 4739篇 |
2019年 | 3354篇 |
2018年 | 2826篇 |
2017年 | 3371篇 |
2016年 | 3591篇 |
2015年 | 4197篇 |
2014年 | 7352篇 |
2013年 | 6464篇 |
2012年 | 8538篇 |
2011年 | 9033篇 |
2010年 | 6898篇 |
2009年 | 7106篇 |
2008年 | 7283篇 |
2007年 | 8535篇 |
2006年 | 7360篇 |
2005年 | 6643篇 |
2004年 | 5469篇 |
2003年 | 4952篇 |
2002年 | 3939篇 |
2001年 | 3233篇 |
2000年 | 2593篇 |
1999年 | 2258篇 |
1998年 | 1624篇 |
1997年 | 1303篇 |
1996年 | 1071篇 |
1995年 | 842篇 |
1994年 | 625篇 |
1993年 | 432篇 |
1992年 | 285篇 |
1991年 | 197篇 |
1990年 | 163篇 |
1989年 | 141篇 |
1988年 | 105篇 |
1987年 | 52篇 |
1986年 | 45篇 |
1985年 | 58篇 |
1984年 | 43篇 |
1983年 | 30篇 |
1982年 | 43篇 |
1981年 | 18篇 |
1980年 | 11篇 |
1979年 | 18篇 |
1978年 | 15篇 |
1977年 | 6篇 |
1959年 | 4篇 |
1951年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Modelling students' behaviours has reached a status that can only be overcome by improving the ability of predicting the results on teamwork. Indeed, teamwork is an important piece on the learning process, but understanding their mechanisms and predicting the results achieved is far from being solved by traditional classifiers. In this paper, we address the problem of predicting teamwork results, and propose a recommender system that suggests new teams, in the context of a given curricular unit. Any student, who is looking for a team, may use the system; in particular, he may ask for the best team to join, either considering all available colleagues or just the set of his previous teammates. Our system makes use of social network analysis and classification methods as the algorithmic core of the decision‐making process. System evaluation is presented through a set of experimental results, which report the performance of social network analysis and classification algorithms over real datasets. 相似文献
992.
基于Hadoop的云端异常流量检测与分析平台 总被引:6,自引:0,他引:6
Hadoop系统作为一种开源的分布式云计算平台已获得广泛应用,但其云端易受到各种威胁和攻击,基于此,开发了一种基于Hadoop的云端异常流量检查与分析平台。首先,使用Mapper周期性地从所有存储流量信息的文件中提取流量的部分信息;然后,通过Reducer将异常流量提取并保存。通过对流量数据的存储、检测与分析可成功地检测出有威胁的攻击,从而保障云端的安全。由于本平台基于开源的Hadoop实现,因此成本较低;同时,基于Java语言实现,可成功移植于各种主流操作系统,具有广泛适用性。基于局域网进行监控试验,结果表明本平台可成功地检测出异常流量,并输出友好的用户界面。 相似文献
993.
994.
This paper is concerned with the synchronization problem about linear singularly perturbed complex network system with coupling delay. The sufficient delay-dependent conditions for the synchronization of the network are established by introducing an equivalent network system with the Lyapunov stability theory. These conditions, which are formulated in terms of linear matrix inequalities, can be solved efficiently by the LMI toolbox of MATLAB. A simulation example is provided to show the validity of the proposed the synchronization conditions of the whole network. 相似文献
995.
Saeed Mehrjoo Abdolhossein Sarrafzadeh Mehrdad Mehrjoo 《Computational Intelligence》2015,31(3):513-531
This article proposes a novel algorithm to improve the lifetime of a wireless sensor network. This algorithm employs swarm intelligence algorithms in conjunction with compressive sensing theory to build up the routing trees and to decrease the communication rate. The main contribution of this article is to extend swarm intelligence algorithms to build a routing tree in such a way that it can be utilized to maximize efficiency, thereby rectifying the delay problem of compressive sensing theory and improving the network lifetime. In addition, our approach offers accurate data recovery from small amounts of compressed data. Simulation results show that our approach can effectively extend the network lifetime of a large‐scale wireless sensor network. 相似文献
996.
The energy savings achieved by implementing energy efficiency (EE) lighting retrofit projects are sometimes not sustainable and vanish rapidly given that lamp population decays as time goes by if without proper maintenance activities. Scope of maintenance activities refers to replacements of failed lamps due to nonrepairable lamp burnouts. Full replacements of all the failed lamps during each maintenance interval contribute to a tight project budget due to the expense for the lamp failure inspections, as well as the procurement and installation of new lamps. Since neither “no maintenance” nor “full maintenance” is preferable to the EE lighting project developers (PDs), we propose to design an optimal maintenance plan that optimises the number of replacements of the failed lamps, such that the EE lighting project achieves sustainable performance in terms of energy savings whereas the PDs obtain their maximum benefits in the sense of cost–benefit ratio. This optimal maintenance planning (OMP) problem is aptly formulated as an optimal control problem under control system framework, and solved by a model predictive control (MPC) approach. An optimal maintenance plan for an EE lighting retrofit project is designed as a case study to illustrate the effectiveness of the proposed control system approach. 相似文献
997.
Model-based control design requires a careful specification of performance and robustness requirements. In typical norm-based control designs, performance and robustness requirements are specified in a scalar optimization criterion, even for complex multivariable systems. This paper aims to develop a novel approach for the formulation of this optimization criterion for multivariable motion systems that exhibit spatio-temporal deformations. To achieve this, characteristics of the underlying system are exploited to design multivariable weighting functions. In contrast to pre-existing approaches, which typically lead to diagonal weighting functions, the proposed approach enables the design of non-diagonal weighting functions. Extensive experimental results confirm that the proposed procedure can significantly improve the performance of an industrial motion system compared to earlier approaches. 相似文献
998.
999.
微博是舆论传播的中心和渠道,同时参与舆论的形成、发展与引导过程,其自媒体发布、意见领袖参与等因素在一定程度上造成了微博谣言、虚假炒作、社会动员等现象。针对炒作微博的传播特点,分析其群体的隐蔽策划现象,挖掘出普通微博和炒作微博在传播网络结构、转发增量统计等方面的差异。通过社交网站的应用程序接口对目标微博的所有评论、转发和点赞用户进行信息获取,构建该微博的传播网络,利用社团模块度、平均最短路径和网络直径这3个属性度量该网络的紧密程度,基于支持向量机对所抽取的微博进行分类,进而识别出炒作微博。实验结果表明,该方法对微博传播用户的属性信息依赖小以及传播网络结构特征敏感,并且具有较高的炒作微博识别准确率。 相似文献
1000.
王华秋 《计算机应用与软件》2015,(2):69-71,202
为了稳定氧化铝深度脱硅过程的热工制度和降低能耗,采用小波神经网络辨识的内模控制方法进行氧化铝深度脱硅工艺过程控制。根据小波基函数的激励强度和衰减程度可以添加或者删除小波神经网络隐含层神经元,从而优化小波神经网络隐含层结构。再用自构建小波神经网络辨识内模控制系统的正模型和逆模型,从而改进神经网络内模控制技术。实验结果表明,所提出的控制方法比传统方法在鲁棒性和抗扰性方面具有更好的性能表现,各项指标均优于传统控制方法,实现了氧化铝深度脱硅工艺优化。 相似文献