全文获取类型
收费全文 | 2970篇 |
免费 | 311篇 |
国内免费 | 224篇 |
专业分类
电工技术 | 42篇 |
综合类 | 100篇 |
化学工业 | 17篇 |
金属工艺 | 47篇 |
机械仪表 | 204篇 |
建筑科学 | 55篇 |
矿业工程 | 21篇 |
能源动力 | 10篇 |
轻工业 | 8篇 |
水利工程 | 3篇 |
石油天然气 | 11篇 |
武器工业 | 13篇 |
无线电 | 313篇 |
一般工业技术 | 67篇 |
冶金工业 | 21篇 |
原子能技术 | 7篇 |
自动化技术 | 2566篇 |
出版年
2024年 | 1篇 |
2023年 | 23篇 |
2022年 | 45篇 |
2021年 | 63篇 |
2020年 | 40篇 |
2019年 | 21篇 |
2018年 | 56篇 |
2017年 | 102篇 |
2016年 | 105篇 |
2015年 | 83篇 |
2014年 | 163篇 |
2013年 | 107篇 |
2012年 | 128篇 |
2011年 | 172篇 |
2010年 | 152篇 |
2009年 | 157篇 |
2008年 | 162篇 |
2007年 | 181篇 |
2006年 | 192篇 |
2005年 | 137篇 |
2004年 | 169篇 |
2003年 | 219篇 |
2002年 | 172篇 |
2001年 | 186篇 |
2000年 | 166篇 |
1999年 | 138篇 |
1998年 | 98篇 |
1997年 | 53篇 |
1996年 | 66篇 |
1995年 | 39篇 |
1994年 | 39篇 |
1993年 | 17篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1965年 | 2篇 |
1962年 | 1篇 |
排序方式: 共有3505条查询结果,搜索用时 31 毫秒
121.
Juyong Zhang Chunlin Wu Jianfei Cai Jianmin Zheng Xue‐cheng Tai 《Computer Graphics Forum》2010,29(2):517-526
This paper considers the problem of interactively finding the cutting contour to extract components from a given mesh. Some existing methods support cuts of arbitrary shape but require careful and tedious input from the user. Others need little user input however they are sensitive to user input and need a postprocessing step to smooth the generated jaggy cutting contours. The popular geometric snake can be used to optimize the cutting contour, but it cannot deal with the topology change. In this paper, we propose a geodesic curvature flow based framework to overcome all these problems. Since in many cases the meaningful cutting contour on a 3D mesh is locally shortest in the sense of some weighted curve length, the geodesic curvature flow is an ideal tool for our problem. It evolves the cutting contour to the nearby local minimum. We should mention that the previous numerical scheme, discretized geodesic curvature flow (dGCF) is too slow and has not been applied to mesh segmentation. With a careful observation to dGCF, we devise here a fast computation scheme called fast geodesic curvature flow (FGCF), which only needs to solve a smaller and easier problem. The initial cutting contour is generated by a variant of random walks algorithm, which is very fast and gives reasonable cutting result with little user input. Experiment results on the benchmark mesh segmentation data set show that our proposed framework is robust to user input and capable of producing good results reflecting geometric features and human shape perception. 相似文献
122.
By modeling mass transfer phenomena, we simulate solids and liquids dissolving or changing to other substances. We also deal with the very small‐scale phenomena that occur when a fluid spreads out at the interface of another fluid. We model the pressure at the interfaces between fluids with Darcy's Law and represent the viscous fingering phenomenon in which a fluid interface spreads out with a fractal‐like shape. We use hybrid grid‐based simulation and smoothed particle hydrodynamics (SPH) to simulate intermolecular diffusion and attraction using particles at a computable scale. We have produced animations showing fluids mixing and objects dissolving. 相似文献
123.
Shin-Chih Tu Guey-Yun Chang Jang-Ping Sheu Wei Li Kun-Ying Hsieh 《Journal of Parallel and Distributed Computing》2010
With the advancement of MEMS technologies, sensor networks have opened up broad application prospects. An important issue in wireless sensor networks is object detection and tracking, which typically involves two basic components, collaborative data processing and object location reporting. The former aims to have sensors collaborating in determining a concise digest of object location information, while the latter aims to transport a concise digest to sink in a timely manner. This issue has been intensively studied in individual objects, such as intruders. However, the characteristic of continuous objects has posed new challenges to this issue. Continuous objects can diffuse, increase in size, or split into multiple continuous objects, such as a noxious gas. In this paper, a scalable, topology-control-based approach for continuous object detection and tracking is proposed. Extensive simulations are conducted, which show a significant improvement over existing solutions. 相似文献
124.
提出了一种基于灰度直方图的目标检测方法。背景差法和帧间差法是两种比较常用的目标检测方法。利用图像灰度直方图进行背景建模,然后提取视频序列中的一帧图像与背景模型进行对比分析,设定一个阈值来判断当前帧与背景模型之间的差异性,以此可以快速判断是否有目标出现。实验结果表明,此方法简单有效、计算复杂度低,能够快速地检测出视频序列中的目标。 相似文献
125.
Integrated earthquake simulation (IES) is a seamless simulation of the three earthquake processes, namely, the earthquake hazard process, the earthquake disaster process and the anti-disaster action process. High performance computing (HPC) is essential if IES, or particularly, the simulation of the earthquake disaster process is applied to an urban area in which 104∼6 structures are located. IES is enhanced with parallel computation, and its performance is examined, so that virtual earthquake disaster simulation will be made for a model of an actual city by inputting observed strong ground motion. It is shown that parallel IES has fairly good scalability even when advanced non-linear seismic structure analysis is used. 相似文献
126.
127.
128.
129.
The present study investigates influences of vibration directions, vibration magnitudes, object sizes, object distances and angles of approach on producing errors while performing pointing and clicking activity on a laptop monitor similar to passengers working on moving trains. Attempts made outside the boundary of an object while performing the activity is registered as an error. The number of errors produced under different exposure conditions is computed. Higher vibration magnitudes, smaller size of the objects, and diagonal angular movements are found to create more errors and affected accuracy of the activity and hence showed difficulties to perform the activity. 相似文献
130.