全文获取类型
收费全文 | 89921篇 |
免费 | 6801篇 |
国内免费 | 3144篇 |
专业分类
电工技术 | 4835篇 |
技术理论 | 10篇 |
综合类 | 4901篇 |
化学工业 | 16008篇 |
金属工艺 | 4709篇 |
机械仪表 | 5545篇 |
建筑科学 | 7391篇 |
矿业工程 | 2057篇 |
能源动力 | 2599篇 |
轻工业 | 5137篇 |
水利工程 | 1544篇 |
石油天然气 | 4742篇 |
武器工业 | 564篇 |
无线电 | 10767篇 |
一般工业技术 | 11687篇 |
冶金工业 | 4768篇 |
原子能技术 | 868篇 |
自动化技术 | 11734篇 |
出版年
2024年 | 345篇 |
2023年 | 1388篇 |
2022年 | 2470篇 |
2021年 | 3335篇 |
2020年 | 2499篇 |
2019年 | 2159篇 |
2018年 | 2421篇 |
2017年 | 2675篇 |
2016年 | 2515篇 |
2015年 | 3145篇 |
2014年 | 4273篇 |
2013年 | 5311篇 |
2012年 | 5498篇 |
2011年 | 5793篇 |
2010年 | 5111篇 |
2009年 | 4906篇 |
2008年 | 4650篇 |
2007年 | 4547篇 |
2006年 | 4788篇 |
2005年 | 4261篇 |
2004年 | 2862篇 |
2003年 | 2568篇 |
2002年 | 2261篇 |
2001年 | 2080篇 |
2000年 | 2336篇 |
1999年 | 2631篇 |
1998年 | 2442篇 |
1997年 | 1941篇 |
1996年 | 1776篇 |
1995年 | 1482篇 |
1994年 | 1247篇 |
1993年 | 909篇 |
1992年 | 678篇 |
1991年 | 548篇 |
1990年 | 410篇 |
1989年 | 379篇 |
1988年 | 318篇 |
1987年 | 173篇 |
1986年 | 154篇 |
1985年 | 106篇 |
1984年 | 92篇 |
1983年 | 60篇 |
1982年 | 58篇 |
1981年 | 51篇 |
1980年 | 37篇 |
1979年 | 34篇 |
1978年 | 13篇 |
1977年 | 33篇 |
1976年 | 16篇 |
1975年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
951.
Jui‐Ming Yeh Chi‐Lun Chen Tai‐Hung Kuo Wen‐Fen Su Hsi‐Ya Huang Der‐Jang Liaw Hsin‐Yi Lu Chi‐Fong Liu Yuan‐Hsiang Yu 《应用聚合物科学杂志》2004,92(2):1072-1079
A series of polymer–clay nanocomposite (PCN) materials consisting of 1,4‐bis(4‐aminophenoxy)‐2‐tert‐butylbenzene–4,4′‐oxydiphthalic anhydride (BATB–ODPA) polyimide (PI) and layered montmorillonite (MMT) clay were successfully prepared by an in situ polymerization reaction through thermal imidization up to 300°C. The synthesized PCN materials were subsequently characterized by Fourier‐Transform infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of material composition on thermal stability, mechanical strength, molecular permeability and optical clarity of bulk PI and PCN materials in the form of membranes were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), molecular permeability analysis (GPA) and ultraviolet‐visible (UV/VIS) transmission spectra, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1072–1079, 2004 相似文献
952.
Fei Yan Josef Kittler David Windridge William Christmas Krystian Mikolajczyk Stephen Cox Qiang Huang 《Image and vision computing》2014
Fully automatic annotation of tennis game using broadcast video is a task with a great potential but with enormous challenges. In this paper we describe our approach to this task, which integrates computer vision, machine listening, and machine learning. At the low level processing, we improve upon our previously proposed state-of-the-art tennis ball tracking algorithm and employ audio signal processing techniques to detect key events and construct features for classifying the events. At high level analysis, we model event classification as a sequence labelling problem, and investigate four machine learning techniques using simulated event sequences. Finally, we evaluate our proposed approach on three real world tennis games, and discuss the interplay between audio, vision and learning. To the best of our knowledge, our system is the only one that can annotate tennis game at such a detailed level. 相似文献
953.
Experimental Study of an EMG-Controlled 5-DOF Anthropomorphic Prosthetic Hand for Motion Restoration
Dapeng Yang Li Jiang Qi Huang Rongqiang Liu Hong Liu 《Journal of Intelligent and Robotic Systems》2014,76(3-4):427-441
In this paper, we attempted to evaluate the performance of an electromyography (EMG)-controlled 5-DOF prosthetic hand on ten transradial amputees. The proposed prosthesis is composed of a five-fingered hand, a passive wrist, and a customized socket for each subject. The EMG control methods included both a commonly used pattern recognition-based scheme (DD-SVM) and a novel digital encoding strategy (double-channel template matching (DCTM)). A virtual 3D hand platform was developed for training the subjects and rapidly testing the control methods. For each subject, the performance of the EMG control methods was firstly measured by off-line classification accuracy; then, according to the accuracy, a particular control method was selected and embedded in the EMG controller for further validation on ordinary daily life activities. Our experiments were conducted to test not only the hand’s grasp ability but also other multifinger cooperation skills. The result indicated that the subjects of rich control experience can accomplish several intuitive motion control over their hands. However, the kinds of the motions and their relative recognition accuracy may depend on some individual differences, such as the amputation level, the activity of the residual nerve-muscle system, and the richness of control experience. Meanwhile, the proposed digital encoding method, DCTM, which only utilized two channels of EMG, was necessary for those amputees with few available control signals. This paper suggested that the EMG control method should be differently considered according to the particular condition of each subject. 相似文献
954.
Lianhang Ma Hao Huang Qinming He Kevin Chiew Zhenguang Liu 《Journal of Intelligent Information Systems》2014,43(1):183-203
Local community detection aims at finding a community structure starting from a seed which is a given vertex in a network without global information, such as online social networks that are too large and dynamic to ever be known fully. Nonetheless, the existing approaches to local community detection are usually sensitive to seeds, i.e., some seeds may lead to missing of some true communities. In this paper, we present a seed-insensitive method called GMAC and its variation iGMAC for local community detection. They estimate the similarity among vertices by investigating vertices’ neighborhoods, and reveal a local community by maximizing its internal similarity and minimizing its external similarity simultaneously. Extensive experimental results on both synthetic and real-world data sets verify the effectiveness of our algorithms. 相似文献
955.
956.
957.
958.
959.
With the fast explosive rate of the amount of image data on the Internet, how to efficiently utilize them in the cross-media scenario becomes an urgent problem. Images are usually accompanied with contextual textual information. These two heterogeneous modalities are mutually reinforcing to make the Internet content more informative. In most cases, visual information can be regarded as an enhanced content of the textual document. To make image-to-image similarity being more consistent with document-to-document similarity, this paper proposes a method to learn image similarities according to the relations of the accompanied textual documents. More specifically, instead of using the static quantitative relations, rank-based learning procedure by employing structural SVM is adopted in this paper, and the ranking structure is established by comparing the relative relations of textual information. The learning results are in more accordance with the human’s recognition. The proposed method in this paper can be used not only for the image-to-image retrieval, but also for cross-modality multimedia, where a query expansion framework is proposed to get more satisfactory results. Extensive experimental evaluations on large scale Internet dataset validate the performance of the proposed methods. 相似文献
960.
Ling Chen Chuandong Li Tingwen Huang Yiran Chen Xin Wang 《Neural computing & applications》2014,25(2):393-400
This letter presents a new memristor crossbar array system and demonstrates its applications in image learning. The controlled pulse and image overlay technique are introduced for the programming of memristor crossbars and promising a better performance for noise reduction. The time-slot technique is helpful for improving the processing speed of image. Simulink and numerical simulations have been employed to demonstrate the useful applications of the proposed circuit structure in image learning. 相似文献