全文获取类型
收费全文 | 25712篇 |
免费 | 2743篇 |
国内免费 | 1793篇 |
专业分类
电工技术 | 2128篇 |
技术理论 | 8篇 |
综合类 | 3429篇 |
化学工业 | 583篇 |
金属工艺 | 222篇 |
机械仪表 | 1146篇 |
建筑科学 | 9320篇 |
矿业工程 | 363篇 |
能源动力 | 475篇 |
轻工业 | 443篇 |
水利工程 | 232篇 |
石油天然气 | 454篇 |
武器工业 | 238篇 |
无线电 | 2726篇 |
一般工业技术 | 1623篇 |
冶金工业 | 448篇 |
原子能技术 | 188篇 |
自动化技术 | 6222篇 |
出版年
2024年 | 116篇 |
2023年 | 319篇 |
2022年 | 593篇 |
2021年 | 667篇 |
2020年 | 722篇 |
2019年 | 565篇 |
2018年 | 587篇 |
2017年 | 698篇 |
2016年 | 887篇 |
2015年 | 1003篇 |
2014年 | 1850篇 |
2013年 | 1536篇 |
2012年 | 1971篇 |
2011年 | 2139篇 |
2010年 | 1872篇 |
2009年 | 1845篇 |
2008年 | 1811篇 |
2007年 | 1963篇 |
2006年 | 1710篇 |
2005年 | 1349篇 |
2004年 | 1061篇 |
2003年 | 883篇 |
2002年 | 723篇 |
2001年 | 613篇 |
2000年 | 558篇 |
1999年 | 451篇 |
1998年 | 313篇 |
1997年 | 233篇 |
1996年 | 199篇 |
1995年 | 197篇 |
1994年 | 149篇 |
1993年 | 117篇 |
1992年 | 119篇 |
1991年 | 62篇 |
1990年 | 58篇 |
1989年 | 66篇 |
1988年 | 48篇 |
1987年 | 30篇 |
1986年 | 30篇 |
1985年 | 21篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 15篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1959年 | 7篇 |
1958年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
为了更为全面地表征语音情感状态,弥补线性情感特征参数在刻画不同情感类型上的不足,将相空间重构理论引入语音情感识别中来,通过分析不同情感状态下的混沌特征,提取Kolmogorov熵和关联维作为新的情感特征参数,并结合传统语音特征使用支持向量机(SVM)进行语音情感识别。实验结果表明,通过引入混沌参数,与传统物理特征进行识别的方案相比,准确率有了一定的提高,为语音情感的识别提供了一个新的研究途径。 相似文献
92.
李洋 《电脑与微电子技术》2014,(9):23-27
就目前高等学校公共基础课程教育的现状,以计算机基础课程为例,探讨如何调整课程内容、尝试新型教学方式,论述如何开展公共基础课程教学方法与手段改革,通过课前、课堂和课后实施教学艺术,加强、充实实训内容,增进网络资源共享课程建设,促进教学质量提高。 相似文献
93.
环境陶艺空间有三大要素特征:其一,思维空间在环境陶艺空间中的特性;其二,环境空间在环境陶艺空间中的特性;其三.陶艺作品空间与心理空间在环境陶艺空间中的特性。通过以上分析,可以看出环境陶艺空间各要素之间相互作用、具有相互依存的空间系统化的关系。 相似文献
94.
State space approach is an effective method to mass-exchange network (MEN) synthesis. By decomposing the network into two interactive parts, a distribution network and a process operator, the synthesis problem can be formulated into a mixed integer nonlinear programming (MINLP) model. In this article, a generalized state space model based on typical MEN is established and verified in two cases. A new asymmetrical operator and cost index are also adopted to speed up the solution process. The results demonstrate the efficiency of the proposed approach. 相似文献
95.
Shu Liang Cheng Peng Zeng Liao Yong Wang 《International journal of systems science》2014,45(10):2203-2212
Approximations for general fractional order dynamic systems are of much theoretical and practical interest. In this paper, a new approximate method for fractional order integrator is proposed. The poles of the approximate model are unrelated to the order of integrator. This feature shows benefits on extending the algorithm to the systems containing various fractional orders. Then a unified approximate method is derived for general fractional order linear or nonlinear dynamic systems via combining the proposed new method with the distributed frequency model approach. Numerical examples are given to show the wide applicability of our method and to illustrate the acceptable accuracy for approximations as well. 相似文献
96.
《Pattern recognition》2014,47(2):833-842
Ensemble clustering is a recently evolving research direction in cluster analysis and has found several different application domains. In this work the complex ensemble clustering problem is reduced to the well-known Euclidean median problem by clustering embedding in vector spaces. The Euclidean median problem is solved by the Weiszfeld algorithm and an inverse transformation maps the Euclidean median back into the clustering domain. In the experiment study different evaluation strategies are considered. The proposed embedding strategy is compared to several state-of-art ensemble clustering algorithms and demonstrates superior performance. 相似文献
97.
Jose María Alvarez-Rodríguez Jose Emilio Labra-Gayo Patricia Ordoñez de Pablos 《Computers in Industry》2014
The present paper introduces and reviews existing technology and research works in the field of e-Procurement. More specifically this survey aims to collect those relevant approaches that have tackled the challenge of delivering more advanced and intelligent e-Procurement management systems due to its relevance in the industry to afford more timely, adaptable and flexible decisions in purchasing processes. Although existing tools and techniques have demonstrated their ability to manage e-Procurement processes as a part of a supply management system there is a lack of interoperability among tools, tangled dependencies between processes or difficulties to exploit existing data and information to name a few that are preventing a proper use of the new dynamic and data-based environment. On the other hand semantic-based technologies emerge to provide the adequate building blocks to represent domain-knowledge and elevate the meaning of information resources through a common and shared data model (RDF) with a formal query language (SPARQL) and accessible via the Internet Protocols. In this sense the Linked Data effort has gained momentum to apply the principles of the aforementioned initiative to boost the re-use of information and data across different tools and processes. That is why authors review both existing open issues in the context e-Procurement with special focus on public procurement and semantic-based approaches to address them. To do so a preliminary research study is conducted to assess the state of the art in the context of e-Procurement and semantic-based systems. Afterwards main drawbacks of existing e-Procurement systems are presented to narrow down in semantic-based approaches applied to this field. Once the current status in both areas is reviewed, authors purpose the use and creation of an e-Procurement index to evaluate the quality of service of procurement systems. In this light the Analytical Hierarchy Process (AHP) method is used to set up an initial weight for each indicator in the index and to perform a first comparison between traditional and semantic-based approaches. Finally some discussion, conclusions and future challenges are also outlined. 相似文献
98.
99.
100.
《Graphical Models》2014,76(2):57-69
This paper presents a novel approach based on the shape space concept to classify deformations of 3D models. A new quasi-conformal metric is introduced which measures the curvature changes at each vertex of each pose during the deformation. The shapes with similar deformation patterns follow a similar deformation curve in shape space. Energy functional of the deformation curve is minimized to calculate the geodesic curve connecting two shapes on the shape space manifold. The geodesic distance illustrates the similarity between two shapes, which is used to compute the similarity between the deformations. We applied our method to classify the left ventricle deformations of myopathic and control subjects, and the sensitivity and specificity of our method were 88.8% and 85.7%, which are higher than other methods based on the left ventricle cavity, which shows our method can quantify the similarity and disparity of the left ventricle motion well. 相似文献