全文获取类型
收费全文 | 2459篇 |
免费 | 142篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 25篇 |
综合类 | 1篇 |
化学工业 | 627篇 |
金属工艺 | 41篇 |
机械仪表 | 56篇 |
建筑科学 | 73篇 |
矿业工程 | 2篇 |
能源动力 | 101篇 |
轻工业 | 169篇 |
水利工程 | 8篇 |
石油天然气 | 4篇 |
无线电 | 282篇 |
一般工业技术 | 487篇 |
冶金工业 | 123篇 |
原子能技术 | 11篇 |
自动化技术 | 592篇 |
出版年
2024年 | 2篇 |
2023年 | 30篇 |
2022年 | 43篇 |
2021年 | 66篇 |
2020年 | 62篇 |
2019年 | 53篇 |
2018年 | 73篇 |
2017年 | 62篇 |
2016年 | 90篇 |
2015年 | 63篇 |
2014年 | 103篇 |
2013年 | 178篇 |
2012年 | 184篇 |
2011年 | 228篇 |
2010年 | 174篇 |
2009年 | 147篇 |
2008年 | 146篇 |
2007年 | 151篇 |
2006年 | 103篇 |
2005年 | 88篇 |
2004年 | 67篇 |
2003年 | 50篇 |
2002年 | 53篇 |
2001年 | 49篇 |
2000年 | 34篇 |
1999年 | 40篇 |
1998年 | 55篇 |
1997年 | 39篇 |
1996年 | 21篇 |
1995年 | 16篇 |
1994年 | 17篇 |
1993年 | 17篇 |
1992年 | 21篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有2602条查询结果,搜索用时 15 毫秒
31.
Magat Julie Ozenne Valéry Cedilnik Nicolas Naulin Jérôme Haliot Kylian Sermesant Maxime Gilbert Stephen H. Trew Mark Haissaguerre Michel Quesson Bruno Bernus Olivier 《Magma (New York, N.Y.)》2021,34(5):741-755
Magnetic Resonance Materials in Physics, Biology and Medicine - The aim of the study is to compare structure tensor imaging (STI) with diffusion tensor imaging (DTI) of the sheep heart... 相似文献
32.
Gigabit home networks represent a key technology to make the Future Internet success a reality. Consumers will require networks to be simple to install, without the need of any new wire and with green consideration. To make this network ubiquitous, seamless and robust, a technology independent MAC layer will ensure its global control and provide connectivities to any number of devices the user wishes to connect to it in any room. In order to make this vision comes true, substantial progress is required in the fields of protocol design and in systems architectures. For this goal, we introduce a new convergence layer denoted inter-MAC, which provides a common infrastructure to the home network, Among the inter-MAC functionalities, we focused the interest on the path selection mechanism including the green aspect. To improve quality of service, reduce energy consumption and radiofrequency devices number, we define a new path selection protocol based on several metrics. We present some preliminary results obtained on an experimental test bed. 相似文献
33.
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
34.
Recent progress in modelling, animation and rendering means that rich, high fidelity virtual worlds are found in many interactive graphics applications. However, the viewer's experience of a 3D world is dependent on the nature of the virtual cinematography, in particular, the camera position, orientation and motion in relation to the elements of the scene and the action. Camera control encompasses viewpoint computation, motion planning and editing. We present a range of computer graphics applications and draw on insights from cinematographic practice in identifying their different requirements with regard to camera control. The nature of the camera control problem varies depending on these requirements, which range from augmented manual control (semi‐automatic) in interactive applications, to fully automated approaches. We review the full range of solution techniques from constraint‐based to optimization‐based approaches, and conclude with an examination of occlusion management and expressiveness in the context of declarative approaches to camera control. 相似文献
35.
Quantum versions of random walks on the line and the cycle show a quadratic improvement over classical random walks in their spreading rates and mixing times, respectively. Non-unitary quantum walks can provide a useful optimisation of these properties, producing a more uniform distribution on the line, and faster mixing times on the cycle. We investigate the interplay between quantum and random dynamics by comparing the resources required, and examining numerically how the level of quantum correlations varies during the walk. We show numerically that the optimal non-unitary quantum walk proceeds such that the quantum correlations are nearly all removed at the point of the final measurement. This requires only O(logT) random bits for a quantum walk of T steps. 相似文献
36.
Lionel Buchaillot Olivier Millet Emmanuel Quévy Dominique Collard 《Microsystem Technologies》2008,14(1):69-78
The paper presents the snap-through phenomenon in the case of micro fabricated clamped-clamped buckled beam. This dynamic
post-buckling behavior is likely to occur in 3D microstructures when they are subjected to large vibration amplitudes. The
main difference between this work and previous studies is the MEMS specific beam dimension, especially the large initial deflection
of the buckled beam that involves the inversion of the two first resonance frequencies. The mathematical development allows
showing how the vibration amplitude of the supporting base affects the post-buckling dynamic behavior of the beam. For each
frequency, the limit between the stable behavior and the snap-through behavior is evaluated. Moreover, the effect of environment
is taken into account from the damping point of view. Samples are fabricated and the experiment is described. Measurements
are compared to the theoretical approach and the results are in good agreement with the proposed model. 相似文献
37.
Thomas Silverston Olivier Fourmaux Alessio Botta Alberto Dainotti Antonio Pescapé Giorgio Ventre Kavé Salamatian 《Computer Networks》2009,53(4):470-484
The Internet is currently experiencing one of the most important challenges in terms of content distribution since its first uses as a medium for content delivery: users from passive downloaders and browsers are moving towards content producers and publishers. They often distribute and retrieve multimedia contents establishing network communities. This is the case of peer-to-peer IPTV communities.In this work we present a detailed study of P2P IPTV traffic, providing useful insights on both transport- and packet-level properties as well as on the behavior of the peers inside the network. In particular, we provide novel results on the (i) ports and protocols used; (ii) differences between signaling and video traffic; (iii) behavior of the traffic at different time scales; (iv) differences between TCP and UDP traffic; (v) traffic generated and received by peers; (vi) peers neighborhood and session duration. The knowledge gained thanks to this analysis is useful for several tasks, e.g. traffic identification, understanding the performance of different P2P IPTV technologies and the impact of such traffic on network nodes and links, and building more realistic models for simulations.1 相似文献
38.
Nicolas Vuillerme Nicolas Pinsault Olivier Chenu Anthony Fleury Yohan Payan Jacques Demongeot 《Pervasive and Mobile Computing》2009,5(3):268-275
We describe the architecture of an original biofeedback system for balance improvement for fall prevention and present results of a feasibility study. The underlying principle of this biofeedback consists of providing supplementary information related to foot sole pressure distribution through a wireless embedded tongue-placed tactile output device.Twelve young healthy adults voluntarily participated in this experiment. They were asked to stand as immobile as possible with their eyes closed in two conditions of no-biofeedback and biofeedback. Centre of foot pressure (CoP) displacements were recorded using a force platform. Results showed reduced CoP displacements in the biofeedback relative to the no-biofeedback condition.On the whole, the present findings evidence the effectiveness of this system in improving postural control on young healthy adults. Further investigations are needed to strengthen the potential clinical value of this device. 相似文献
39.
Engineering Transition Metal Layers for Long Lasting Anionic Redox in Layered Sodium Manganese Oxide
Natalia Voronina Jun Ho Yu Hee Jae Kim Najma Yaqoob Olivier Guillon Hyungsub Kim Min-Gi Jung Hun-Gi Jung Koji Yazawa Hitoshi Yashiro Payam Kaghazchi Seung-Taek Myung 《Advanced functional materials》2023,33(5):2210423
Oxygen-redox-based-layered cathode materials are of great importance in realizing high-energy-density sodium-ion batteries (SIBs) that can satisfy the demands of next-generation energy storage technologies. However, Mn-based-layered materials (P2-type Na-poor Nay[AxMn1−x]O2, where A = alkali ions) still suffer from poor reversibility during oxygen-redox reactions and low conductivity. In this work, the dual Li and Co replacement is investigated in P2-type-layered NaxMnO2. Experimentally and theoretically, it is demonstrated that the efficacy of the dual Li and Co replacement in Na0.6[Li0.15Co0.15Mn0.7]O2 is that it improves the structural and cycling stability despite the reversible Li migration from the transition metal layer during de-/sodiation. Operando X-ray diffraction and ex situ neutron diffraction analysis prove that the material maintains a P2-type structure during the entire range of Na+ extraction and insertion with a small volume change of ≈4.3%. In Na0.6[Li0.15Co0.15Mn0.7]O2, the reversible electrochemical activity of Co3+/Co4+, Mn3+/Mn4+, and O2-/(O2)n- redox is identified as a reliable mechanism for the remarkable stable electrochemical performance. From a broader perspective, this study highlights a possible design roadmap for developing cathode materials with optimized cationic and anionic activities and excellent structural stabilities for SIBs. 相似文献
40.
Chapellier Paul Lavenus Pierre Le Traon Olivier Dulmet Bernard 《Microsystem Technologies》2022,28(6):1485-1496
Microsystem Technologies - This paper presents recent advances on two dimensional length-extension mode (2D-LEM) quartz resonators providing high quality (Q) factor on resonances at a few MHz. The... 相似文献