全文获取类型
收费全文 | 2578篇 |
免费 | 193篇 |
国内免费 | 88篇 |
专业分类
电工技术 | 103篇 |
综合类 | 126篇 |
化学工业 | 521篇 |
金属工艺 | 84篇 |
机械仪表 | 98篇 |
建筑科学 | 406篇 |
矿业工程 | 39篇 |
能源动力 | 50篇 |
轻工业 | 85篇 |
水利工程 | 52篇 |
石油天然气 | 68篇 |
武器工业 | 11篇 |
无线电 | 168篇 |
一般工业技术 | 249篇 |
冶金工业 | 543篇 |
原子能技术 | 49篇 |
自动化技术 | 207篇 |
出版年
2023年 | 17篇 |
2022年 | 26篇 |
2021年 | 36篇 |
2020年 | 44篇 |
2019年 | 42篇 |
2018年 | 46篇 |
2017年 | 48篇 |
2016年 | 80篇 |
2015年 | 93篇 |
2014年 | 121篇 |
2013年 | 120篇 |
2012年 | 123篇 |
2011年 | 151篇 |
2010年 | 93篇 |
2009年 | 103篇 |
2008年 | 109篇 |
2007年 | 122篇 |
2006年 | 118篇 |
2005年 | 121篇 |
2004年 | 159篇 |
2003年 | 203篇 |
2002年 | 112篇 |
2001年 | 138篇 |
2000年 | 65篇 |
1999年 | 88篇 |
1998年 | 43篇 |
1997年 | 39篇 |
1996年 | 51篇 |
1995年 | 28篇 |
1994年 | 28篇 |
1993年 | 19篇 |
1992年 | 21篇 |
1991年 | 15篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 19篇 |
1987年 | 13篇 |
1986年 | 15篇 |
1985年 | 13篇 |
1984年 | 22篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 22篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 25篇 |
1975年 | 10篇 |
1974年 | 6篇 |
排序方式: 共有2859条查询结果,搜索用时 15 毫秒
1.
Zhijiang Li Yingping Zheng Liqin Cao Lei Jiao Yanfei Zhong Caiyi Zhang 《Color research and application》2020,45(4):656-670
Image color clustering is a basic technique in image processing and computer vision, which is often applied in image segmentation, color transfer, contrast enhancement, object detection, skin color capture, and so forth. Various clustering algorithms have been employed for image color clustering in recent years. However, most of the algorithms require a large amount of memory or a predetermined number of clusters. In addition, some of the existing algorithms are sensitive to the parameter configurations. In order to tackle the above problems, we propose an image color clustering method named Student's t-based density peaks clustering with superpixel segmentation (tDPCSS), which can automatically obtain clustering results, without requiring a large amount of memory, and is not dependent on the parameters of the algorithm or the number of clusters. In tDPCSS, superpixels are obtained based on automatic and constrained simple non-iterative clustering, to automatically decrease the image data volume. A Student's t kernel function and a cluster center selection method are adopted to eliminate the dependence of the density peak clustering on parameters and the number of clusters, respectively. The experiments undertaken in this study confirmed that the proposed approach outperforms k-means, fuzzy c-means, mean-shift clustering, and density peak clustering with superpixel segmentation in the accuracy of the cluster centers and the validity of the clustering results. 相似文献
2.
3.
介绍用已知年龄和烧结温度的古陶片穆斯堡尔超精细参数与年龄和烧结温度的实验关系曲线作基础,应用计算机模拟程序,自动求出未知陶片的年龄和最高烧结温度的方法。 相似文献
4.
堇青石基玻璃陶瓷的制备与展望 总被引:2,自引:0,他引:2
介绍了制备堇青石基玻璃陶瓷的三种方法:熔融法、烧结法和溶胶-凝胶法,综述了玻璃组成、添加剂和成核剂对堇青石基玻璃陶瓷的烧结及性能的影响,并对其未来的发展进行了展望。 相似文献
5.
Two commercial Pt modified aluminide coatings (RT22 and MDC150L) on the same single crystal Ni-based superalloy (CMSX-4) were studied by: scanning electron microscopy; transmission electron microscopy; energy dispersive X-ray spectrometry; and gravimetry. The RT22 coating is an inward grown coating (high activity), while MDC150L is produced by outward growth (low activity). Samples were oxidised in still laboratory air at 1050 °C for various times up to 2000 h. It was found that the outward grown coating produced a slower growing oxide that was more spallation resistant. Several possible reasons for this were identified including: coating purity; coating surface topography; and ductile to brittle transition temperature. The microstructural differences between the two coatings in the as-coated condition were investigated and the development of their microstructure during heat treatment was described. A model for coating growth during heat treatment was proposed. 相似文献
6.
Masami Ikeda Susumu Fukumoto Hiroshi Takao Shinya Ohtsuka Eiichi Haginomori Masayuki Hikita 《Electrical Engineering in Japan》2002,141(4):16-24
This paper describes the dielectric breakdown characteristics of oil and oil‐impregnated paper for very fast transient (VFT) voltages. Blumlein circuits generate VFT voltages of 60 and 300 ns in a pulse width that simulates disconnecting switching surges in gas‐insulated switch gears. We measured the breakdown voltages of needle‐to‐plane, plane‐to‐plane oil gaps and several pieces of paper between plane electrodes for VFT and lightning impulse voltages. The measured data were formulated in V‐t characteristics and Weibull probability distributions. The inclination n of V‐t characteristics of insulating paper is 150, which is less than n = 13.7 of the plane‐to‐plane oil gap in the VFT time range. The shape parameters of Weibull distribution obtained in this study show that the scattering of breakdown voltages of paper is much less than that of oil. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 16–24, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10043 相似文献
7.
8.
9.
根据转炉炼钢的物理化学反应机理,从质量平衡和能量平衡的计算出发,通过小参数变动,导出了增量式静态模型中矿石方程和供氧方程的系数。所得结论与新日铁资料基本相符。同时,还进行了炉料和产物的计算,分析了改变废钢比对生产的影响。 相似文献
10.
用电话网实现远程监控自动化 总被引:1,自引:0,他引:1
彭启候 《水电自动化与大坝监测》2002,26(4):70-73
分析了偏僻高山上通信机房和电气房要进行监控的内容和特点等,探讨 了用经济、可靠的电话交换网实现远程监控自动化的方案和实施办法。该设计根据监控对象 的特点,利用现有的电话网络和程控交换机实现远程监控,不需要专用通信传输通道,不需 要增加硬件和软件,成本低,技术成熟,容易实现。 相似文献