全文获取类型
收费全文 | 14996篇 |
免费 | 3477篇 |
国内免费 | 2376篇 |
专业分类
电工技术 | 645篇 |
综合类 | 1782篇 |
化学工业 | 228篇 |
金属工艺 | 543篇 |
机械仪表 | 1276篇 |
建筑科学 | 305篇 |
矿业工程 | 124篇 |
能源动力 | 173篇 |
轻工业 | 312篇 |
水利工程 | 73篇 |
石油天然气 | 321篇 |
武器工业 | 125篇 |
无线电 | 3269篇 |
一般工业技术 | 1230篇 |
冶金工业 | 308篇 |
原子能技术 | 72篇 |
自动化技术 | 10063篇 |
出版年
2024年 | 212篇 |
2023年 | 496篇 |
2022年 | 764篇 |
2021年 | 874篇 |
2020年 | 867篇 |
2019年 | 591篇 |
2018年 | 504篇 |
2017年 | 627篇 |
2016年 | 651篇 |
2015年 | 773篇 |
2014年 | 1080篇 |
2013年 | 967篇 |
2012年 | 1337篇 |
2011年 | 1398篇 |
2010年 | 1194篇 |
2009年 | 1170篇 |
2008年 | 1186篇 |
2007年 | 1212篇 |
2006年 | 958篇 |
2005年 | 884篇 |
2004年 | 664篇 |
2003年 | 580篇 |
2002年 | 405篇 |
2001年 | 296篇 |
2000年 | 228篇 |
1999年 | 194篇 |
1998年 | 162篇 |
1997年 | 102篇 |
1996年 | 95篇 |
1995年 | 70篇 |
1994年 | 61篇 |
1993年 | 38篇 |
1992年 | 29篇 |
1991年 | 19篇 |
1990年 | 29篇 |
1989年 | 24篇 |
1988年 | 18篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 19篇 |
1984年 | 12篇 |
1983年 | 15篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1959年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Rectangular section control technology(RSCT)was introduced to achieve high-precision profile control during silicon steel rolling.The RSCT principle and method were designed,and the whole RSCT control strategy was developed.Specifically,RSCT included roll contour design,rolling technology optimization,and control strategy development,aiming at both hot strip mills(HSMs)and cold strip mills(CSMs).Firstly,through the high-performance variable crown(HVC)work roll optimization design in the upper-stream stands and the limited shifting technology for schedule-free rolling in the downstream stands of HSMs,a hot strip with a stable crown and limited wedge,local spot,and single wave was obtained,which was suitable for cold rolling.Secondly,an approximately rectangular section was obtained by edge varying contact(EVC)work roll contour design,edge-drop setting control,and closed loop control in the upper-stream stands of CSMs.Moreover,complex-mode flatness control was realized by coordinating multiple shape-control methods in the downstream stands of CSMs.In addition,the RSCT approach was applied in several silicon-steel production plants,where an outstanding performance and remarkable economic benefits were observed. 相似文献
2.
Clip-art image segmentation is widely used as an essential step to solve many vision problems such as colorization and vectorization. Many of these applications not only demand accurate segmentation results, but also have little tolerance for time cost, which leads to the main challenge of this kind of segmentation. However, most existing segmentation techniques are found not sufficient for this purpose due to either their high computation cost or low accuracy. To address such issues, we propose a novel segmentation approach, ECISER, which is well-suited in this context. The basic idea of ECISER is to take advantage of the particular nature of cartoon images and connect image segmentation with aliased rasterization. Based on such relationship, a clip-art image can be quickly segmented into regions by re-rasterization of the original image and several other computationally efficient techniques developed in this paper. Experimental results show that our method achieves dramatic computational speedups over the current state-of-the-art approaches, while preserving almost the same quality of results. 相似文献
3.
ABSTRACTThis paper proposes the multiple-hypotheses image segmentation and feed-forward neural network classifier for food recognition to improve the performance. Initially, the food or meal image is given as input. Then, the segmentation is applied to identify the regions, where a particular food item is located using salient region detection, multi-scale segmentation, and fast rejection. Then, the features of every food item are extracted by the global feature and local feature extraction. After the features are obtained, the classification is performed for each segmented region using a feed-forward neural network model. Finally, the calorie value is computed with the aid of (i) food volume and (ii) calorie and nutrition measure based on mass value. The experimental results and performance evaluation are validated. The outcome of the proposed method attains 0.947 for Macro Average Accuracy (MAA) and 0.959 for Standard Accuracy (SA), which provides better classification performance. 相似文献
4.
Modern methods of determining fracture resistance are analyzed. The necessity of developing a crucially new method based on edge chipping of a brittle material is shown. The results of experimental studies are presented. The applicability of the method to the comparative fracture resistance evaluation of ceramics is substantiated. 相似文献
5.
Cluster analysis in industrial market segmentation through artificial neural network 总被引:6,自引:0,他引:6
Market segmentation has commonly applied cluster analysis. This study intends to make the comparison of conventional two-stage method with proposed two-stage method through the simulated data. The proposed two-stage method is the combination of self-organizing feature maps and K-means method. The simulation results show that the proposed scheme is better than the conventional two-stage method based on the rate of misclassification. 相似文献
6.
介绍了高上山成型法的工艺特点及理论上的可行性和实践中的可靠性,此方法能有效地解决薄钢带波浪状边缘的焊接方面存在的问题。 相似文献
7.
Joon C. Park Author Vitae Author Vitae 《Computer aided design》2003,35(9):807-812
Presented in this paper is a topology reconstruction algorithm from a set of unorganized trimmed surfaces. Error-prone small geometric elements are handled to give proper topological information. It gives complete topology to topologically complete models, and it is also tolerant to incomplete models. The proposed algorithm is vertex-based in that clues for topological information are searched from the set of vertices first, not from that of edges. 相似文献
8.
A Novel Segmentation and Feedback Model for Resolving Contention in Optical Burst Switching 总被引:2,自引:0,他引:2
A novel segmentation and feedback model (SFM) applied to resolve contention is proposed. Simulation and performance analyses show that the SFM effectively avoids contentions in optical burst switching (OBS). The long delay time of deflection routing and the immature technology of wavelength converters and optical buffers are not deployed in the SFM. The SFM does not only realize fast switching but also allows preemption by higher priority bursts. 相似文献
9.
An elastic half plane with an oblique edge crack is considered in this paper. A pair of concentrated forces or point dislocations is assumed to act at an arbitrary point in the half plane. The half plane with an edge crack is first mapped into a unit circle by a rational mapping function so that the following analysis can be carried out on the mapped plane analytically. Then the complex stress functions are derived by separating the whole problem into two parts; one is the principal part corresponding to the infinite plane acted on by concentrated forces or dislocations, the other is the holomorphic part, which can be determined by making use of the property of regularity of complex stress functions. The stress intensity factors of the crack can be calculated with different inclined angles of the crack, and the displacement and stress components at an arbitrary position in the half plane can be expressed explicitly. 相似文献
10.
Gabriel Tsechpenakis Dimitris Metaxas Carol Neidle 《Computer Vision and Image Understanding》2006,104(2-3):140
We present a data-driven dynamic coupling between discrete and continuous methods for tracking objects of high dofs, which overcomes the limitations of previous techniques. In our approach, two trackers work in parallel, and the coupling between them is based on the tracking error. We use a model-based continuous method to achieve accurate results and, in cases of failure, we re-initialize the model using our discrete tracker. This method maintains the accuracy of a more tightly coupled system, while increasing its efficiency. At any given frame, our discrete tracker uses the current and several previous frames to search into a database for the best matching solution. For improved robustness, object configuration sequences, rather than single configurations, are stored in the database. We apply our framework to the problem of 3D hand tracking from image sequences and the discrimination between fingerspelling and continuous signs in American Sign Language. 相似文献