全文获取类型
收费全文 | 3011篇 |
免费 | 202篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 47篇 |
综合类 | 16篇 |
化学工业 | 692篇 |
金属工艺 | 88篇 |
机械仪表 | 74篇 |
建筑科学 | 271篇 |
矿业工程 | 24篇 |
能源动力 | 90篇 |
轻工业 | 147篇 |
水利工程 | 28篇 |
石油天然气 | 2篇 |
无线电 | 232篇 |
一般工业技术 | 671篇 |
冶金工业 | 133篇 |
原子能技术 | 11篇 |
自动化技术 | 694篇 |
出版年
2024年 | 5篇 |
2023年 | 66篇 |
2022年 | 90篇 |
2021年 | 117篇 |
2020年 | 106篇 |
2019年 | 102篇 |
2018年 | 120篇 |
2017年 | 95篇 |
2016年 | 148篇 |
2015年 | 134篇 |
2014年 | 155篇 |
2013年 | 221篇 |
2012年 | 235篇 |
2011年 | 266篇 |
2010年 | 173篇 |
2009年 | 164篇 |
2008年 | 162篇 |
2007年 | 163篇 |
2006年 | 98篇 |
2005年 | 85篇 |
2004年 | 76篇 |
2003年 | 51篇 |
2002年 | 64篇 |
2001年 | 28篇 |
2000年 | 26篇 |
1999年 | 29篇 |
1998年 | 32篇 |
1997年 | 32篇 |
1996年 | 22篇 |
1995年 | 19篇 |
1994年 | 14篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1972年 | 2篇 |
1961年 | 2篇 |
排序方式: 共有3220条查询结果,搜索用时 0 毫秒
971.
Wiebel A Garth C Scheuermann G 《IEEE transactions on visualization and computer graphics》2007,13(4):641-651
We present, extend, and apply a method to extract the contribution of a sub-region of a data set to the global flow. To isolate this contribution, we decompose the flow in the subregion into a potential flow that is induced by the original flow on the boundary and a localized flow. The localized flow is obtained by subtracting the potential flow from the original flow. Since the potential flow is free of both divergence and rotation, the localized flow retains the original features and captures the region-specific flow that contains the local contribution of the considered subdomain to the global flow. In the remainder of the paper, we describe an implementation on unstructured grids in both two and three dimensions for steady and unsteady flow fields. We discuss the application of some widely used feature extraction methods on the localized flow and describe applications like reverse-flow detection using the potential flow. Finally, we show that our algorithm is robust and scalable by applying it to various flow data sets and giving performance figures. 相似文献
972.
Mü ller Christoph Frey Steffen Strengert Magnus Dachsbacher Carsten Ertl Thomas 《IEEE transactions on visualization and computer graphics》2009,15(4):605-617
We present a development environment for distributed GPU computing targeted for multi-GPU systems, as well as graphics clusters. Our system is based on CUDA and logically extends its parallel programming model for graphics processors to higher levels of parallelism, namely, the PCI bus and network interconnects. While the extended API mimics the full function set of current graphics hardware—including the concept of global memory—on all distribution layers, the underlying communication mechanisms are handled transparently for the application developer. To allow for high scalability, in particular for network-interconnected environments, we introduce an automatic GPU-accelerated scheduling mechanism that is aware of data locality. This way, the overall amount of transmitted data can be heavily reduced, which leads to better GPU utilization and faster execution. We evaluate the performance and scalability of our system for bus and especially network-level parallelism on typical multi-GPU systems and graphics clusters. 相似文献
973.
Thomas Schmickl Ronald Thenius Christoph Moeslinger Gerald Radspieler Serge Kernbach Marc Szymanski Karl Crailsheim 《Autonomous Agents and Multi-Agent Systems》2009,18(1):133-155
We demonstrate the ability of a swarm of autonomous micro-robots to perform collective decision making in a dynamic environment.
This decision making is an emergent property of decentralized self-organization, which results from executing a very simple
bio-inspired algorithm. This algorithm allows the robotic swarm to choose from several distinct light sources in the environment
and to aggregate in the area with the highest illuminance. Interestingly, these decisions are formed by the collective, although
no information is exchanged by the robots. The only communicative act is the detection of robot-to-robot encounters. We studied
the performance of the robotic swarm under four environmental conditions and investigated the dynamics of the aggregation
behaviour as well as the flexibility and the robustness of the solutions. In summary, we can report that the tested robotic
swarm showed two main characteristic features of swarm systems: it behaved flexible and the achieved solutions were very robust.
This was achieved with limited individual sensor abilities and with low computational effort on each single robot in the swarm. 相似文献
974.
975.
Christoph Schneeweiß 《OR Spectrum》1994,16(2):161-168
Zusammenfassung Die Arbeit stellt einen konzeptionellen Rahmen zur Modellierung hierarchischer Planungsprobleme bereit, indem sie die Ebenen der hierarchischen Planung als Stufen eines dynamischen Programms interpretiert. Wesentlich ist hierbei, daß die unteren Ebenen zunächst nur approximativ antizipiert werden und eine genauere Beschreibung erst in nach unten fortschreitender (rollierender) Planung erfolgt. An einigen Beispielen wird gezeigt, wie sich die vorhandenen hierarchischen Modelle in dem allgemeinen Rahmen beschreiben lassen, und es wird angedeutet, welcher Zusammenhang zu hierarchischen Algorithmen, Agency-Fragestellungen und hierarchischen Aushandlungen besteht. 相似文献
976.
Christoph Schnörr 《Journal of Mathematical Imaging and Vision》1994,4(2):189-198
We propose the minimization of a nonquadratic functional or, equivalently, a nonlinear diffusion model to smooth noisy image functionsg: R
n R while preserving significant transitions of the data. The model is chosen such that important properties of the conventional quadratic-functional approach still hold: (1) existence of a unique solution continuously depending on the datag and (2) stability of approximations using the standard finite-element method. Relations with other global approaches for the segmentation of image data are discussed. Numerical experiments with real data illustrate this approach.This work was supported by the ESPRIT project SUBSYM. 相似文献
977.
Manman Hu Andi Muhammad Risqi Jianchang Wu Liang Chen Jaewang Park Seung-Un Lee Hyun-Sung Yun Byung-Wook Park Christoph J. Brabec Sang Il Seok 《Advanced functional materials》2023,33(29):2300693
Improving the performance, reproducibility, and stability of Sn-based perovskite solar cells (PSCs) with n–i–p structures is an important challenge. Spiro-OMeTAD [2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene], a hole transporting material (HTM) with n–i–p structure, requires the oxygen exposure after addition of Li-TFSI [Lithium bis(trifluoromethanesulfonyl)imide] as a dopant to increase the hole concentration. In Sn-based PSC, Sn2+ is easily oxidized to Sn4+ under such a condition, resulting in a sharp decrease in efficiency. Herein, a formamidinium tin triiodide (FASnI3)-based PSCs fabricated using DPI-TPFB [4-Isopropyl-4′-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate] instead of Li-TFSI are reported as a dopant in Spiro-OMeTAD. The DPI-TPFB enables the fabrication of PSCs with an efficiency of up to 10.9%, the highest among FASnI3-based PSCs with n–i–p structures. Moreover, ≈80% of the initial efficiency is maintained even after 1,597 h under maximum power point tracking conditions. In particular, the encapsulated device does not show any decrease in efficiency even after holding for 50 h in the 85 °C/85% RH condition. The high efficiency and excellent stability of PSCs prepared by doping with DPI-TPFB are attributed to not only increasing electrical conductivity by acting as a Lewis acid, but also stabilizing Sn2+ through coordination with Sn2+ on the surface of FASnI3. 相似文献
978.
Virtual Reality - A “virtual mirror” is a promising interface for virtual or augmented reality applications in which users benefit from seeing themselves within the environment, such as... 相似文献
979.
A visual short-term memory task was more strongly disrupted by visual than spatial interference, and a spatial memory task was simultaneously more strongly disrupted by spatial than visual interference. This double dissociation supports a fractionation of visuospatial short-term memory into separate visual and spatial components. In 6 experiments, this interpretation could be defended against alternative explanations in terms of trade-offs in resource allocation between memory tasks and interference tasks, in terms of an involvement of short-term consolidation and long-term memory, in terms of differential phonological-loop and central-executive involvement, and in terms of similarity-based interference. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
980.
Gamma oscillations and stimulus selection 总被引:1,自引:0,他引:1
More coherent excitatory stimuli are known to have a competitive advantage over less coherent ones. We show here that this advantage is amplified greatly when the target includes inhibitory interneurons acting via GABA(A)-receptor-mediated synapses and the coherent input oscillates at gamma frequency. We hypothesize that therein lies, at least in part, the functional significance of the experimentally observed link between attentional biasing of stimulus competition and gamma frequency rhythmicity. 相似文献