全文获取类型
收费全文 | 60911篇 |
免费 | 2571篇 |
国内免费 | 71篇 |
专业分类
电工技术 | 402篇 |
综合类 | 49篇 |
化学工业 | 12098篇 |
金属工艺 | 1082篇 |
机械仪表 | 1075篇 |
建筑科学 | 1853篇 |
矿业工程 | 106篇 |
能源动力 | 1537篇 |
轻工业 | 8739篇 |
水利工程 | 516篇 |
石油天然气 | 285篇 |
武器工业 | 6篇 |
无线电 | 3053篇 |
一般工业技术 | 9556篇 |
冶金工业 | 14791篇 |
原子能技术 | 341篇 |
自动化技术 | 8064篇 |
出版年
2023年 | 475篇 |
2022年 | 895篇 |
2021年 | 1496篇 |
2020年 | 1064篇 |
2019年 | 1111篇 |
2018年 | 1925篇 |
2017年 | 1921篇 |
2016年 | 2042篇 |
2015年 | 1530篇 |
2014年 | 2036篇 |
2013年 | 3874篇 |
2012年 | 3310篇 |
2011年 | 3520篇 |
2010年 | 2730篇 |
2009年 | 2554篇 |
2008年 | 2634篇 |
2007年 | 2289篇 |
2006年 | 1825篇 |
2005年 | 1544篇 |
2004年 | 1426篇 |
2003年 | 1285篇 |
2002年 | 1134篇 |
2001年 | 770篇 |
2000年 | 760篇 |
1999年 | 972篇 |
1998年 | 4818篇 |
1997年 | 2902篇 |
1996年 | 2004篇 |
1995年 | 1168篇 |
1994年 | 984篇 |
1993年 | 959篇 |
1992年 | 327篇 |
1991年 | 360篇 |
1990年 | 321篇 |
1989年 | 322篇 |
1988年 | 290篇 |
1987年 | 266篇 |
1986年 | 262篇 |
1985年 | 313篇 |
1984年 | 227篇 |
1983年 | 168篇 |
1982年 | 206篇 |
1981年 | 221篇 |
1980年 | 196篇 |
1979年 | 149篇 |
1978年 | 142篇 |
1977年 | 294篇 |
1976年 | 634篇 |
1975年 | 113篇 |
1973年 | 105篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Joris Vaillant Abderrahmane Kheddar Hervé Audren François Keith Stanislas Brossette Adrien Escande Karim Bouyarmane Kenji Kaneko Mitsuharu Morisawa Pierre Gergondet Eiichi Yoshida Suuji Kajita Fumio Kanehiro 《Autonomous Robots》2016,40(3):561-580
We describe the research and the integration methods we developed to make the HRP-2 humanoid robot climb vertical industrial-norm ladders. We use our multi-contact planner and multi-objective closed-loop control formulated as a QP (quadratic program). First, a set of contacts to climb the ladder is planned off-line (automatically or by the user). These contacts are provided as an input for a finite state machine. The latter builds supplementary tasks that account for geometric uncertainties and specific grasps procedures to be added to the QP controller. The latter provides instant desired states in terms of joint accelerations and contact forces to be tracked by the embedded low-level motor controllers. Our trials revealed that hardware changes are necessary, and parts of software must be made more robust. Yet, we confirmed that HRP-2 has the kinematic and power capabilities to climb real industrial ladders, such as those found in nuclear power plants and large scale manufacturing factories (e.g. aircraft, shipyard) and construction sites. 相似文献
992.
Tegawendé F. Bissyandé Laurent Réveillère Julia L. Lawall Gilles Muller 《Automated Software Engineering》2016,23(1):3-41
The Linux kernel does not export a stable, well-defined kernel interface, complicating the development of kernel-level services, such as device drivers and file systems. While there does exist a set of functions that are exported to external modules, this set of functions frequently changes, and the functions have implicit, ill-documented preconditions. No specific debugging support is provided. We present Diagnosys, an approach to automatically constructing a debugging interface for the Linux kernel. First, a designated kernel maintainer uses Diagnosys to identify constraints on the use of the exported functions. Based on this information, developers of kernel services can then use Diagnosys to generate a debugging interface specialized to their code. When a service including this interface is tested, it records information about potential problems. This information is preserved following a kernel crash or hang. Our experiments show that the generated debugging interface provides useful log information and incurs a low performance penalty. 相似文献
993.
João André Cristina Santos Lino Costa 《Journal of Intelligent and Robotic Systems》2016,82(3-4):379-397
Robots must be able to adapt their motor behavior to unexpected situations in order to safely move among humans. A necessary step is to be able to predict failures, which result in behavior abnormalities and may cause irrecoverable damage to the robot and its surroundings, i.e. humans. In this paper we build a predictive model of sensor traces that enables early failure detection by means of a skill memory. Specifically, we propose an architecture based on a biped locomotion solution with improved robustness due to sensory feedback, and extend the concept of Associative Skill Memories (ASM) to periodic movements by introducing several mechanisms into the training workflow, such as linear interpolation and regression into a Dynamical Motion Primitive (DMP) system such that representation becomes time invariant and easily parameterizable. The failure detection mechanism applies statistical tests to determine the optimal operating conditions. Both training and failure testing were conducted on a DARwIn-OP inside a simulation environment to assess and validate the failure detection system proposed. Results show that the system performance in terms of the compromise between sensitivity and specificity is similar with and without the proposed mechanism, while achieving a significant data size reduction due to the periodic approach taken. 相似文献
994.
F.?PérezEmail author A.?Pérez M.?Rodríguez E.?Magdaleno 《Journal of Mathematical Imaging and Vision》2016,56(3):573-590
The Focal Stack Transform integrates a 4D lightfield over a set of appropriately chosen 2D planes. The result of such integration is an image focused on a determined depth in 3D space. The set of such images is the Focal Stack of the lightfield. This paper studies the existence of an inverse for this transform. Such inverse could be used to obtain a 4D lightfield from a set of images focused on several depths of the scene. In this paper, we show that this inversion cannot be obtained for a general lightfield and introduce a subset of lightfields where this inversion can be computed exactly. We examine the numerical properties of such inversion process for general lightfields and examine several regularization approaches to stabilize the transform. Experimental results are provided for focal stacks obtained from several plenoptic cameras. From a practical point of view, results show how this inversion procedure can be used to recover, compress, and denoise the original 4D lightfield. 相似文献
995.
In real manufacturing environments, the control of some elements in systems based on robotic cells, such as transport robots has some difficulties when planning operations dynamically. The Job Shop scheduling Problem with Transportation times and Many Robots (JSPT-MR) is a generalization of the classical Job Shop scheduling Problem (JSP) where a set of jobs additionally have to be transported between machines by several transport robots. Hence, the JSPT-MR is more computationally difficult than the JSP presenting two NP-hard problems simultaneously: the job shop scheduling problem and the robot routing problem. This paper proposes a hybrid metaheuristic approach based on clustered holonic multiagent model for the JSPT-MR. Firstly, a scheduler agent applies a Neighborhood-based Genetic Algorithm (NGA) for a global exploration of the search space. Secondly, a set of cluster agents uses a tabu search technique to guide the research in promising regions. Computational results are presented using two sets of benchmark literature instances. New upper bounds are found, showing the effectiveness of the presented approach. 相似文献
996.
Collision avoidance is essential for safe robot manipulation. Especially with humans around, robots should work only when safety can be robustly guaranteed. In this paper, we propose using virtual impedance control for reactive, smooth, and consistent collision avoidance that interferes minimally with the original task. The virtual impedance control operates in the risk space, a vector space describing the possibilities of all forthcoming collisions, and is designed to elude all risks in a consistent response in order to create assuring human-robot interaction experiences. The proposed scheme intrinsically handles kinematic singularity and the activation of avoidance using a boundary layer defined on the spectrum of Jacobian. In cooperation with the original controller, the proposed avoidance scheme provides a proof of convergence if the original controller is stable with and without projection. In simulations and experiments, we verified the characteristics of the proposed control scheme and integrated the system with Microsoft Kinect to monitor the workspace for real-time collision detection and avoidance. The results show that the proposed approach is suitable for robot operation with humans nearby. 相似文献
997.
Radu Horaud Miles Hansard Georgios Evangelidis Clément Ménier 《Machine Vision and Applications》2016,27(7):1005-1020
Time-of-flight (TOF) cameras are sensors that can measure the depths of scene points, by illuminating the scene with a controlled laser or LED source and then analyzing the reflected light. In this paper, we will first describe the underlying measurement principles of time-of-flight cameras, including: (1) pulsed-light cameras, which measure directly the time taken for a light pulse to travel from the device to the object and back again, and (2) continuous-wave-modulated light cameras, which measure the phase difference between the emitted and received signals, and hence obtain the travel time indirectly. We review the main existing designs, including prototypes as well as commercially available devices. We also review the relevant camera calibration principles, and how they are applied to TOF devices. Finally, we discuss the benefits and challenges of combined TOF and color camera systems. 相似文献
998.
Emanuele Maiorana Jordi Solé-Casals Patrizio Campisi 《Machine Vision and Applications》2016,27(8):1351-1360
Electroencephalography (EEG) has been recently investigated as a biometric modality for automatic people recognition purposes. Several studies have shown that brain signals possess subject-specific traits that allow distinguishing people. Nonetheless, extracting discriminative characteristics from EEG recordings may be a challenging task, due to the significant presence of artifacts in the acquired data. In order to cope with such issue, in this paper we evaluate the effectiveness of some preprocessing techniques in automatically removing undesired EEG contributions, with the aim of improving the achievable recognition rates. Specifically, methods based on blind source separation and sample entropy estimation are here investigated. An extensive set of experimental tests, performed over a large database comprising recordings taken from 50 healthy subjects during three distinct sessions spanning a period of about one month, in both eyes-closed and eyes-open conditions, is carried out to analyze the performance of the proposed approaches. 相似文献
999.
Ilaria Castellani Mariangiola Dezani-Ciancaglini Jorge A. Pérez 《Formal Aspects of Computing》2016,28(4):669-696
We present a comprehensive model of structured communications in which self-adaptation and security concerns are jointly addressed. More specifically, we propose a model of multiparty, self-adaptive communications with access control and secure information flow guarantees. In our model, multiparty protocols (choreographies) are described as global types; security violations occur when process implementations of protocol participants attempt to read or write messages of inappropriate security levels within directed exchanges. Such violations trigger adaptation mechanisms that prevent the violations to occur and/or to propagate their effect in the choreography. Our model is equipped with local and global adaptation mechanisms for reacting to security violations of different gravity; type soundness results ensure that the overall multiparty protocol is still correctly executed while the system adapts itself to preserve the participants’ security. 相似文献
1000.
Juan C. Granda Pelayo Nuño Julio Molleda Rubén Usamentiaga Daniel F. García 《Multimedia Systems》2016,22(5):543-557
Real-time interactive multimedia communications are becoming increasingly useful for education, business, e-commerce and e-government, providing an enriched user experience in teleconferencing, e-meetings, distance training and product demonstrations. Large corporations are usually located at several sites, so real-time multipoint sessions within corporations are especially difficult. IP multicast is available or feasible within each site of an organization. Thus, corporate networks can be considered as various multicast-capable networks interconnected through a wide area network without multicast connectivity. This paper proposes a resilient self-managed overlay network to support real-time multipoint interactive sessions within corporate networks. The proposed overlay takes advantage of the configuration of corporate networks to self-organize and provide an efficient media delivery service, making use of multicast communications wherever available. Various self-healing techniques are implemented allowing for the continuity of ongoing sessions in spite of network disruptions and entity failures. Extensive simulations and tests have been carried out to assess the performance and resilience of the overlay facing several types of disruptions. 相似文献