全文获取类型
收费全文 | 7995篇 |
免费 | 619篇 |
国内免费 | 238篇 |
专业分类
电工技术 | 233篇 |
综合类 | 260篇 |
化学工业 | 1810篇 |
金属工艺 | 426篇 |
机械仪表 | 331篇 |
建筑科学 | 408篇 |
矿业工程 | 135篇 |
能源动力 | 396篇 |
轻工业 | 885篇 |
水利工程 | 99篇 |
石油天然气 | 226篇 |
武器工业 | 13篇 |
无线电 | 813篇 |
一般工业技术 | 1231篇 |
冶金工业 | 367篇 |
原子能技术 | 108篇 |
自动化技术 | 1111篇 |
出版年
2024年 | 26篇 |
2023年 | 119篇 |
2022年 | 241篇 |
2021年 | 295篇 |
2020年 | 279篇 |
2019年 | 263篇 |
2018年 | 314篇 |
2017年 | 400篇 |
2016年 | 397篇 |
2015年 | 272篇 |
2014年 | 425篇 |
2013年 | 761篇 |
2012年 | 573篇 |
2011年 | 547篇 |
2010年 | 406篇 |
2009年 | 413篇 |
2008年 | 330篇 |
2007年 | 287篇 |
2006年 | 215篇 |
2005年 | 159篇 |
2004年 | 201篇 |
2003年 | 278篇 |
2002年 | 387篇 |
2001年 | 330篇 |
2000年 | 173篇 |
1999年 | 106篇 |
1998年 | 140篇 |
1997年 | 70篇 |
1996年 | 67篇 |
1995年 | 51篇 |
1994年 | 29篇 |
1993年 | 29篇 |
1992年 | 27篇 |
1991年 | 25篇 |
1990年 | 21篇 |
1989年 | 24篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 15篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 15篇 |
1982年 | 11篇 |
1981年 | 13篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1976年 | 10篇 |
1970年 | 5篇 |
1906年 | 5篇 |
排序方式: 共有8852条查询结果,搜索用时 0 毫秒
81.
Stephen Abell Nhan Do 《International Journal of Parallel, Emergent and Distributed Systems》2016,31(5):450-468
This article presents a GPU-based single-unit deadlock detection methodology and its algorithm, GPU-OSDDA. Our GPU-based design utilizes parallel hardware of GPU to perform computations and thus is able to overcome the major limitation of prior hardware-based approaches by having the capability of handling thousands of processes and resources, whilst achieving real-world run-times. By utilizing a bit-vector technique for storing algorithm matrices and designing novel, efficient algorithmic methods, we not only reduce memory usage dramatically but also achieve two orders of magnitude speedup over CPU equivalents. Additionally, GPU-OSDDA acts as an interactive service to the CPU, because all of the aforementioned computations and matrix management techniques take place on the GPU, requiring minimal interaction with the CPU. GPU-OSDDA is implemented on three GPU cards: Tesla C2050, Tesla K20c, and Titan X. Our design shows overall speedups of 6-595X over CPU equivalents. 相似文献
82.
83.
Do?Yeon?Kim Guozhong?Li Seong?Taek?Park Mi?Hyun?KoEmail author 《Journal in Computer Virology》2016,12(3):151-161
This paper analyzed the effects of security risk factors fit for cloud computing paradigm on the acceptance of enterprise cloud service with intent to illuminate the factors for vitalizing the adoption of corporate cloud services in the future. The acceptance intention was set as a dependent variable. Independent variables were set in reference to the technology acceptance theory. Security risks were categorized into compliance risk, information leakage risk, troubleshooting risk and service discontinuation risk to design a model for analysis. 相似文献
84.
Rotman lenses are used to obtain multiple beams from a single array. Although the beams produced by the feed antennas at focal points have no path length errors, the beams produced by feed antennas at off focal points may have large path length errors. These path length errors cause deterioration in the multiple beams. In this article, two novel methods are introduced to obtain feed curves which reduce the path length errors of off focal feed points significantly, compared with the commonly used circular and elliptical feed curves. The first method obtains feed curve points based on having zero path length error at three chosen points of the radiating array for each beam direction. The second method uses the particle swarm optimization method for obtaining optimum feed points for each beam direction. The results show that there is a very significant drop in the level of the maximum path length errors (in the order of about 1:4). © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 23: 634–638, 2013. 相似文献
85.
With the emergence of new media, interactive film projects have mainly struggled to resolve the contradiction between dramatic structures and interaction. Dramatic film presents identification with the main character, where the viewer is constantly oppressed by the narrative, and therefore lost in illusion. In this context, when we bring on the scene interaction, the drama apparently starts to lose its power. In this article, a new interactive film model based on Brechtian film theory is proposed. This model presents a new way of spatiotemporal construction where different audiovisual combinations can be viewed successively, and this way the viewer can actively construct his/her own story. Theoretical framework of the Brechtian interactive film model is supported by an interactive film application, named Academia. The main feature of the model is that, while interaction is very simple, the continuity of the narrative is preserved and the film requiring an intellectual level of interpretation. 相似文献
86.
Juha K. Laurila Daniel Gatica-Perez Imad Aad Jan Blom Olivier Bornet Trinh Minh Tri Do Olivier Dousse Julien Eberle Markus Miettinen 《Pervasive and Mobile Computing》2013,9(6):752-771
This paper presents an overview of the Mobile Data Challenge (MDC), a large-scale research initiative aimed at generating innovations around smartphone-based research, as well as community-based evaluation of mobile data analysis methodologies. First, we review the Lausanne Data Collection Campaign (LDCC), an initiative to collect unique longitudinal smartphone dataset for the MDC. Then, we introduce the Open and Dedicated Tracks of the MDC, describe the specific datasets used in each of them, discuss the key design and implementation aspects introduced in order to generate privacy-preserving and scientifically relevant mobile data resources for wider use by the research community, and summarize the main research trends found among the 100+ challenge submissions. We finalize by discussing the main lessons learned from the participation of several hundred researchers worldwide in the MDC Tracks. 相似文献
87.
Since humans are fundamentally social beings and interact frequently with others in their daily life, understanding social context is of primary importance in building context-aware applications. In this paper, using smartphone Bluetooth as a proximity sensor to create social networks, we present a probabilistic approach to mine human interaction types in real life. Our analysis is conducted on Bluetooth data continuously sensed with smartphones for over one year from 40 individuals who are professionally or personally related. The results show that the model can automatically discover a variety of social contexts. We objectively validated our model by studying its predictive and retrieval performance. 相似文献
88.
三峡水情遥测系统中心站在通信组网设计上采用甚高频(VHF)、公共交换电话网络(PSTN)、全球移动通信系统(GSM)、北斗卫星和海事卫星5种通信方式,在系统软件设计上采用了客户/服务器(C/S)的结构模式。实践证明,三峡水情遥测系统中心站既保证了三峡水情遥测系统非常高的畅通率和准确率,又降低了通信成本;既保证了三峡梯级水库调度、防洪、发电和航运的要求,同时还为系统运行维护工作提供了方便。 相似文献
89.
Miloš Hašan Edgar Velázquez‐Armendáriz Fabio Pellacini Kavita Bala 《Computer Graphics Forum》2008,27(4):1105-1114
Rendering animations of scenes with deformable objects, camera motion, and complex illumination, including indirect lighting and arbitrary shading, is a long‐standing challenge. Prior work has shown that complex lighting can be accurately approximated by a large collection of point lights. In this formulation, rendering of animation sequences becomes the problem of efficiently shading many surface samples from many lights across several frames. This paper presents a tensor formulation of the animated many‐light problem, where each element of the tensor expresses the contribution of one light to one pixel in one frame. We sparsely sample rows and columns of the tensor, and introduce a clustering algorithm to select a small number of representative lights to efficiently approximate the animation. Our algorithm achieves efficiency by reusing representatives across frames, while minimizing temporal flicker. We demonstrate our algorithm in a variety of scenes that include deformable objects, complex illumination and arbitrary shading and show that a surprisingly small number of representative lights is sufficient for high quality rendering. We believe out algorithm will find practical use in applications that require fast previews of complex animation. 相似文献
90.
Abstract: Application of the Doppler ultrasound technique in the diagnosis of heart diseases has been increasing in the last decade since it is non‐invasive, practicable and reliable. In this study, a new approach based on the discrete hidden Markov model (DHMM) is proposed for the diagnosis of heart valve disorders. For the calculation of hidden Markov model (HMM) parameters according to the maximum likelihood approach, HMM parameters belonging to each class are calculated by using training samples that only belong to their own classes. In order to calculate the parameters of DHMMs, not only training samples of the related class but also training samples of other classes are included in the calculation. Therefore HMM parameters that reflect a class's characteristics are more represented than other class parameters. For this aim, the approach was to use a hybrid method by adapting the Rocchio algorithm. The proposed system was used in the classification of the Doppler signals obtained from aortic and mitral heart valves of 215 subjects. The performance of this classification approach was compared with the classification performances in previous studies which used the same data set and the efficiency of the new approach was tested. The total classification accuracy of the proposed approach (95.12%) is higher than the total accuracy rate of standard DHMM (94.31%), continuous HMM (93.5%) and support vector machine (92.67%) classifiers employed in our previous studies and comparable with the performance levels of classifications using artificial neural networks (95.12%) and fuzzy‐C‐means/CHMM (95.12%). 相似文献