全文获取类型
收费全文 | 12013篇 |
免费 | 892篇 |
国内免费 | 402篇 |
专业分类
电工技术 | 201篇 |
综合类 | 727篇 |
化学工业 | 358篇 |
金属工艺 | 465篇 |
机械仪表 | 994篇 |
建筑科学 | 224篇 |
矿业工程 | 228篇 |
能源动力 | 161篇 |
轻工业 | 180篇 |
水利工程 | 45篇 |
石油天然气 | 123篇 |
武器工业 | 55篇 |
无线电 | 798篇 |
一般工业技术 | 671篇 |
冶金工业 | 398篇 |
原子能技术 | 164篇 |
自动化技术 | 7515篇 |
出版年
2023年 | 45篇 |
2022年 | 50篇 |
2021年 | 63篇 |
2020年 | 93篇 |
2019年 | 79篇 |
2018年 | 120篇 |
2017年 | 245篇 |
2016年 | 270篇 |
2015年 | 280篇 |
2014年 | 579篇 |
2013年 | 445篇 |
2012年 | 587篇 |
2011年 | 1051篇 |
2010年 | 643篇 |
2009年 | 556篇 |
2008年 | 635篇 |
2007年 | 690篇 |
2006年 | 576篇 |
2005年 | 515篇 |
2004年 | 514篇 |
2003年 | 602篇 |
2002年 | 501篇 |
2001年 | 439篇 |
2000年 | 423篇 |
1999年 | 470篇 |
1998年 | 543篇 |
1997年 | 405篇 |
1996年 | 356篇 |
1995年 | 272篇 |
1994年 | 187篇 |
1993年 | 186篇 |
1992年 | 149篇 |
1991年 | 126篇 |
1990年 | 82篇 |
1989年 | 65篇 |
1988年 | 96篇 |
1987年 | 38篇 |
1986年 | 52篇 |
1985年 | 73篇 |
1984年 | 54篇 |
1983年 | 39篇 |
1982年 | 20篇 |
1981年 | 28篇 |
1980年 | 12篇 |
1979年 | 15篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1974年 | 4篇 |
1972年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
991.
Pairwise Meta-Modeling of Multivariate Output Computer Models Using Nonseparable Covariance Function
Yongxiang Li 《技术计量学》2016,58(4):483-494
Gaussian process (GP) is a popular method for emulating deterministic computer simulation models. Its natural extension to computer models with multivariate outputs employs a multivariate Gaussian process (MGP) framework. Nevertheless, with significant increase in the number of design points and the number of model parameters, building an MGP model is a very challenging task. Under a general MGP model framework with nonseparable covariance functions, we propose an efficient meta-modeling approach featuring a pairwise model building scheme. The proposed method has excellent scalability even for a large number of output levels. Some properties of the proposed method have been investigated and its performance has been demonstrated through several numerical examples. Supplementary materials for this article are available online. 相似文献
992.
Xingbao Tao Wei Peng Dashuai Xie Chongbo Zhao 《International Journal of Food Properties》2017,20(12):3056-3063
A novel technology based on computer vision system (CVS) and artificial neural network (ANN) was developed for the quality evaluation of Hanyuan Zanthoxylum bungeanum Maxim (HZB). The quality evaluation of HZB mainly depended on its colour, odour substances, and impurities. In this study, the contents of volatile oil (VOC), total alkylamides (TALC) and impurities (IMC) were determined and used as indices for quality control of HZB. Furthermore, CVS was also performed to determine the colour parameters (RGB values) and further transforms to CIE L*, a*, and b*. Then, ANN was carried out to analyse the correlations between colour values obtained by CVS and quality parameters of HZB (VOC, TALC, and IMC). Higher performance and stability were presented by using CVS for determining the coloristic values of HZB. In addition, the present results also showed that the established method based on ANN could be used to predict the VOC, TALC, and IMC of HZB with the R2 values of 0.9991, 0.9995, and 0.9998, respectively. This novel technology based on CVS combined with ANN could be used for the rapid, non-destructive, and effective evaluation of the quality of HZB. 相似文献
993.
The likelihood of cyber-attacks against information systems and related production control systems has increased. In order to lower the risk of cyber-attacks, OS makers release timely security updates. However, the amount of time that is available for applying patches is limited on production control systems and the possibility of side effects is a concern. Therefore, we focused on the patch application cycle and the period of pretest, and proposed optimal OS measures for production control systems. We presented the method for quantifying the risk of cyber-attacks on production control systems due to security patches not being applied and for expressing the risk as a monetary amount. This method was also proposed for deriving the patch application cycle, the number of applications, and the optimum test duration. We concluded that this method help to understand the patch management and related security measure and to protect production control systems from cyber-attacks. 相似文献
994.
《Journal of Visual Communication and Image Representation》2014,25(2):263-272
A computer vision-based wayfinding and navigation aid can improve the mobility of blind and visually impaired people to travel independently. In this paper, we develop a new framework to detect and recognize stairs, pedestrian crosswalks, and traffic signals based on RGB-D (Red, Green, Blue, and Depth) images. Since both stairs and pedestrian crosswalks are featured by a group of parallel lines, we first apply Hough transform to extract the concurrent parallel lines based on the RGB (Red, Green, and Blue) channels. Then, the Depth channel is employed to recognize pedestrian crosswalks and stairs. The detected stairs are further identified as stairs going up (upstairs) and stairs going down (downstairs). The distance between the camera and stairs is also estimated for blind users. Furthermore, the traffic signs of pedestrian crosswalks are recognized. The detection and recognition results on our collected datasets demonstrate the effectiveness and efficiency of our proposed framework. 相似文献
995.
We present a user‐guided, semi‐automatic approach to completing large holes in a mesh. The reconstruction of the missing features in such holes is usually ambiguous. Thus, unsupervised methods may produce unsatisfactory results. To overcome this problem, we let the user indicate constraints by providing merely four points per important feature curve on the mesh. Our algorithm regards this input as an indication of an important broken feature curve. Our completion is formulated as a global energy minimization problem, with user‐defined spatial‐coherence constraints, allows for completion that adheres to the existing features. We demonstrate the method on example problems that are not handled satisfactorily by fully automatic methods. 相似文献
996.
Usually visualization is applied to gain insight into data. Yet consuming the data in form of visual representation is not always enough. Instead, users need to edit the data, preferably through the same means used to visualize them. In this work, we present a semi‐automatic approach to visual editing of graphs. The key idea is to use an interactive EditLens that defines where an edit operation affects an already customized and established graph layout. Locally optimal node positions within the lens and edge routes to connected nodes are calculated according to different criteria. This spares the user much manual work, but still provides sufficient freedom to accommodate application‐dependent layout constraints. Our approach utilizes the advantages of multi‐touch gestures, and is also compatible with classic mouse and keyboard interaction. Preliminary user tests have been conducted with researchers from bio‐informatics who need to manually maintain a slowly, but constantly growing molecular network. As the user feedback indicates, our solution significantly improves the editing procedure applied so far. 相似文献
997.
本文研究大学计算机基础课程的主要实验类型及特点,基于自主设计与创新型实验方法构建引导型创新实验模型,并给出具体实现方案,以弥补自主设计与创新实验缺乏指导作用、不易管理的缺点。 相似文献
998.
Miguel A. Otaduy Rasmus Tamstorf Denis Steinemann Markus Gross 《Computer Graphics Forum》2009,28(2):559-568
We present an algorithm for robust and efficient contact handling of deformable objects. By being aware of the internal dynamics of the colliding objects, our algorithm provides smooth rolling and sliding, stable stacking, robust impact handling, and seamless coupling of heterogeneous objects, all in a unified manner. We achieve dynamicsawareness through a constrained dynamics formulation with implicit complementarity constraints, and we present two major contributions that enable an efficient solution of the constrained dynamics problem: a time stepping algorithm that robustly ensures non-penetration and progressively refines the formulation of constrained dynamics, and a new solver for large mixed linear complementarity problems, based on iterative constraint anticipation. We show the application of our algorithm in challenging scenarios such as multi-layered cloth moving at high velocities, or colliding deformable solids simulated with large time steps. 相似文献
999.
1000.