全文获取类型
收费全文 | 2633篇 |
免费 | 112篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 27篇 |
化学工业 | 424篇 |
金属工艺 | 38篇 |
机械仪表 | 26篇 |
建筑科学 | 74篇 |
矿业工程 | 12篇 |
能源动力 | 33篇 |
轻工业 | 753篇 |
水利工程 | 18篇 |
石油天然气 | 2篇 |
无线电 | 183篇 |
一般工业技术 | 470篇 |
冶金工业 | 294篇 |
原子能技术 | 6篇 |
自动化技术 | 392篇 |
出版年
2023年 | 21篇 |
2022年 | 16篇 |
2021年 | 47篇 |
2020年 | 32篇 |
2019年 | 31篇 |
2018年 | 56篇 |
2017年 | 61篇 |
2016年 | 101篇 |
2015年 | 71篇 |
2014年 | 90篇 |
2013年 | 155篇 |
2012年 | 138篇 |
2011年 | 122篇 |
2010年 | 120篇 |
2009年 | 110篇 |
2008年 | 136篇 |
2007年 | 107篇 |
2006年 | 91篇 |
2005年 | 64篇 |
2004年 | 60篇 |
2003年 | 46篇 |
2002年 | 60篇 |
2001年 | 28篇 |
2000年 | 28篇 |
1999年 | 32篇 |
1998年 | 96篇 |
1997年 | 54篇 |
1996年 | 54篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 21篇 |
1992年 | 13篇 |
1976年 | 19篇 |
1937年 | 11篇 |
1936年 | 29篇 |
1935年 | 32篇 |
1934年 | 21篇 |
1933年 | 21篇 |
1932年 | 16篇 |
1931年 | 25篇 |
1930年 | 24篇 |
1929年 | 20篇 |
1928年 | 46篇 |
1927年 | 36篇 |
1926年 | 14篇 |
1925年 | 23篇 |
1915年 | 16篇 |
1913年 | 49篇 |
1912年 | 28篇 |
1907年 | 13篇 |
排序方式: 共有2752条查询结果,搜索用时 15 毫秒
31.
Stangegaard M Frøslev TG Frank-Hansen R Hansen AJ Morling N 《Journal of laboratory automation》2011,16(2):134-140
We have implemented and validated automated protocols for DNA extraction and PCR setup using a Tecan Freedom EVO liquid handler mounted with the Te-MagS magnetic separation device (Tecan, M?nnedorf, Switzerland). The protocols were validated for accredited forensic genetic work according to ISO 17025 using the Qiagen MagAttract DNA Mini M48 kit (Qiagen GmbH, Hilden, Germany) from fresh whole blood and blood from deceased individuals. The workflow was simplified by returning the DNA extracts to the original tubes minimizing the risk of misplacing samples. The tubes that originally contained the samples were washed with MilliQ water before the return of the DNA extracts. The PCR was setup in 96-well microtiter plates. The methods were validated for the kits: AmpF?STR Identifiler, SGM Plus and Yfiler (Applied Biosystems, Foster City, CA), GenePrint FFFL and PowerPlex Y (Promega, Madison, WI). The automated protocols allowed for extraction and addition of PCR master mix of 96 samples within 3.5h. In conclusion, we demonstrated that (1) DNA extraction with magnetic beads and (2) PCR setup for accredited, forensic genetic short tandem repeat typing can be implemented on a simple automated liquid handler leading to the reduction of manual work, and increased quality and throughput. 相似文献
32.
Arnaud Fréville Saïd Hanafi Frédéric Semet Nicolas Yanev 《Computers & Operations Research》2010,37(10):1688-1696
This article proposes a tabu search approach to solve a mathematical programming formulation of the linear classification problem, which consists of determining an hyperplane that separates two groups of points as well as possible in ?m. The tabu search approach proposed is based on a non-standard formulation using linear system infeasibility. The search space is the set of bases defined on the matrix that describes the linear system. The moves are performed by pivoting on a specified row and column. On real machine learning databases, our approach compares favorably with implementations based on parametric programming and irreducible infeasible constraint sets. Additional computational results for randomly generated instances confirm that our method provides a suitable alternative to the mixed integer programming formulation that is solved by a commercial code when the number of attributes m increases. 相似文献
33.
Luca Bertelli Shivkumar Chandrasekaran Frédéric Gibou B. S. Manjunath 《International Journal of Computer Vision》2010,90(3):267-282
In this paper we introduce novel regularization techniques for level set segmentation that target specifically the problem
of multiphase segmentation. When the multiphase model is used to obtain a partitioning of the image in more than two regions,
a new set of issues arise with respect to the single phase case in terms of regularization strategies. For example, if smoothing
or shrinking each contour individually could be a good model in the single phase case, this is not necessarily true in the
multiphase scenario. 相似文献
34.
Stéphane Zieba Philippe Polet Frédéric Vanderhaegen Serge Debernard 《Cognition, Technology & Work》2010,12(3):193-203
Unmanned ground vehicles tend to be more and more autonomous, but both complete teleoperation and full autonomy are not efficient
enough to deal with all possible situations. To be efficient, the human–robot system must be able to anticipate, react and
recover from errors of different kinds, i.e., to be resilient. From this observation, this paper proposes a survey on the
resilience of a human–machine system and the means to control the resilience. The resilience of a system can be defined as
the ability to maintain or recover a stable state when subject to disturbance. Adjustable autonomy and human–machine cooperation
are considered as means of resilience for the system. This paper then proposes three indicators to assess different meanings
of resilience of the system: foresight and avoidance of events, reaction to events and recovery from occurrence of events.
The third of these metrics takes into consideration the concept of affordances that allows a common representation for the
opportunities of action between the automated system and its environment. 相似文献
35.
Roberto Sanchez Geneviève Dauphin-Tanguy Xavier Guillaud Frédéric Colas 《Simulation Modelling Practice and Theory》2010,18(9):1185-1198
This paper proposes a model of a three phase electrical inverter with a LC output filter in delta connection used in a renewable energy supply system. The concept of inverse bond graph via bicausality is used for the control law design. The control law robustness is tested by connecting passive and active (induction machine) loads. 相似文献
36.
This article deals with a local improvement of domain decomposition methods for 2-dimensional elliptic problems for which
either the geometry or the domain decomposition presents conical singularities. After explaining the main results of the theoretical
analysis carried out in Chniti et al. (Calcolo 45, 2008), the numerical experiments presented in this article confirm the optimality properties of the new interface conditions. 相似文献
37.
The bilateral filter is a nonlinear filter that smoothes a signal while preserving strong edges. It has demonstrated great
effectiveness for a variety of problems in computer vision and computer graphics, and fast versions have been proposed. Unfortunately,
little is known about the accuracy of such accelerations. In this paper, we propose a new signal-processing analysis of the
bilateral filter which complements the recent studies that analyzed it as a PDE or as a robust statistical estimator. The
key to our analysis is to express the filter in a higher-dimensional space where the signal intensity is added to the original
domain dimensions. Importantly, this signal-processing perspective allows us to develop a novel bilateral filtering acceleration
using downsampling in space and intensity. This affords a principled expression of accuracy in terms of bandwidth and sampling.
The bilateral filter can be expressed as linear convolutions in this augmented space followed by two simple nonlinearities.
This allows us to derive criteria for downsampling the key operations and achieving important acceleration of the bilateral
filter. We show that, for the same running time, our method is more accurate than previous acceleration techniques. Typically,
we are able to process a 2 megapixel image using our acceleration technique in less than a second, and have the result be
visually similar to the exact computation that takes several tens of minutes. The acceleration is most effective with large
spatial kernels. Furthermore, this approach extends naturally to color images and cross bilateral filtering. 相似文献
38.
A.B. Moreno A. Sánchez E. Frías-Martínez J.F. Vélez 《Engineering Applications of Artificial Intelligence》2009,22(8):1233-1244
Applications related to game technology, law-enforcement, security, medicine or biometrics are becoming increasingly important, which, combined with the proliferation of three-dimensional (3D) scanning hardware, have made that 3D face recognition is now becoming a promising and feasible alternative to two-dimensional (2D) face methods. The main advantage of 3D data, when compared with traditional 2D approaches, is that it provides information that is invariant to rigid geometric transformations and to pose and illumination conditions. One key element for any 3D face recognition system is the modeling of the available scanned data. This paper presents new 3D models for facial surface representation and evaluates them using two matching approaches: one based on support vector machines and another one on principal component analysis (with a Euclidean classifier). Also, two types of environments were tested in order to check the robustness of the proposed models: a controlled environment with respect to facial conditions (i.e. expressions, face rotations, etc.) and a non-controlled one (presenting face rotations and pronounced facial expressions). The recognition rates obtained using reduced spatial resolution representations (a 77.86% for non-controlled environments and a 90.16% for controlled environments, respectively) show that the proposed models can be effectively used for practical face recognition applications. 相似文献
39.
Christiane Jasmin Reinert‐Weiss Holger Baur Sheikh Abdullah Al Nusayer David Duhme Norbert Frühauf 《Journal of the Society for Information Display》2017,25(2):90-97
Conventional adaptive driving beam headlamps are limited in achieving still higher quantities of switchable pixels by the number of LEDs and movable elements needed. In this paper, it is shown that by integrating an active matrix liquid crystal display module, it is possible to realize fully adaptive high‐resolution headlights without mechanical elements and a finite number of LED with 30 k switchable pixels. 相似文献
40.
Road‐Centered Map‐Aided Localization for Driverless Cars Using Single‐Frequency GNSS Receivers 下载免费PDF全文
Zui Tao Philippe Bonnifait Vincent Frémont Javier Ibanez‐Guzman Stéphane Bonnet 《野外机器人技术杂志》2017,34(5):1010-1033
Accurate localization with high availability is a key requirement for autonomous vehicles. It remains a major challenge when using automotive sensors such as single‐frequency Global Navigation Satellite System (GNSS) receivers, a lane detection camera, and proprioceptive sensors. This paper describes a method that enables the estimation of stand‐alone single‐frequency GNSS errors by integrating the measurements from a forward‐looking camera matched with lane markings stored in a digital map. It includes a parameter identification method for a shaping model, which is evaluated using experimental data. An algebraic observability study is then conducted to prove that the proposed state vector is fully observable in a road‐oriented frame. This observability property is the basis to develop a road‐centered Extended Kalman filter (EKF) that can maintain the observability of every component of the state vector on any road, whatever its orientation. To accomplish this, the filter needs to handle road changes, which it does using bijective transformations. The filter was implemented and tested intensely on an experimental vehicle for driverless valet parking services. Field results have shown that the performance of the estimation process is better than solutions based on EKF implemented in a fixed working frame. The proposed filter guarantees that the drift along the road direction remains bounded. This is very important when the vehicle navigates autonomously. Furthermore, the road‐centered modeling improves the accuracy, consistency, and robustness of the localization solver. 相似文献