首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   99428篇
  免费   8019篇
  国内免费   4272篇
电工技术   5611篇
技术理论   6篇
综合类   6248篇
化学工业   16548篇
金属工艺   6150篇
机械仪表   6952篇
建筑科学   8064篇
矿业工程   3402篇
能源动力   2905篇
轻工业   6272篇
水利工程   1658篇
石油天然气   7330篇
武器工业   805篇
无线电   10692篇
一般工业技术   11561篇
冶金工业   4891篇
原子能技术   1010篇
自动化技术   11614篇
  2024年   449篇
  2023年   1772篇
  2022年   3114篇
  2021年   4260篇
  2020年   3311篇
  2019年   2695篇
  2018年   2907篇
  2017年   3283篇
  2016年   3038篇
  2015年   4104篇
  2014年   4901篇
  2013年   5834篇
  2012年   6297篇
  2011年   6724篇
  2010年   5768篇
  2009年   5509篇
  2008年   5362篇
  2007年   5080篇
  2006年   5409篇
  2005年   4710篇
  2004年   2989篇
  2003年   2832篇
  2002年   2657篇
  2001年   2414篇
  2000年   2327篇
  1999年   2638篇
  1998年   2085篇
  1997年   1730篇
  1996年   1701篇
  1995年   1411篇
  1994年   1155篇
  1993年   737篇
  1992年   646篇
  1991年   438篇
  1990年   350篇
  1989年   301篇
  1988年   227篇
  1987年   150篇
  1986年   122篇
  1985年   70篇
  1984年   53篇
  1983年   44篇
  1982年   41篇
  1981年   28篇
  1980年   25篇
  1979年   16篇
  1978年   1篇
  1965年   1篇
  1959年   2篇
  1951年   1篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
112.
113.
114.
115.
为促进S1000D标准在以信息化为中心的综合保障技术中的应用,提高装备技术文档制作和发布的正确性和效率,文章研究了S1000D标准对PDF格式发布样式的规定,分析了XSL的工作原理和各类技术信息的Schema模式,利用XSL-FO技术编写了把数据模块发布成PDF格式的XML文档,通过XMLSPY实现了技术文档的发布;通过实例展示了实现规定的发布样式的关键技术以及从数据模块到PDF发布样式的显示效果,证明了所用方法的正确性与实用性,为实现S1000D标准下的技术信息发布提供了新的可行方法.  相似文献   
116.
Floc architecture of bioflocculation sediment by ESEM and CLSM   总被引:1,自引:0,他引:1  
Huiming Z  Hongwei F  Minghong C 《Scanning》2011,33(6):437-445
Sediment flocculation is a critical component for the understanding of cohesive sediment dynamics. Traditionally, the referred study has largely been devoted to forming mechanism, influencing factors and physicochemical sediment conditions of all kinds of organic-flocculation and inorganic-flocculation. However, during the last decade, the bioflocculation of sediment by biological activity has been given increasing attention. But most studies have focused on the interrelations between biological and sedimentological variables. With the assistance of a newly developed field kit and correlative microscopy (which includes environmental scanning electron microscopy and confocal laser scanning microscopy), this article begins to bridge the resolution gap between sediment particles and biological activities as well as its metabolic products biofilm, in order to better understand the role of polymeric material biofilm in floc ultrastructure and outward floc behavior of bioflocculation sediment. Results have demonstrated that bioflocculation sediment was observed to be composed of complex networks of biofilm and appeared to be of complicated physical floc structures. The biofilm was found to embed particles and permeate the void space, representing the dominant physical bridging mechanism of the flocs and contributed to the extensive surface area, architecture characteristics, and mechanical properties of bioflocculation sediment.  相似文献   
117.
Social navigation enables emergent collaboration between independent collaborators by exposing the behavior of each individual. This is a powerful idea for web-based visualization, where the work of one user can inform other users interacting with the same visualization. Results from a crowdsourced user study evaluating the value of such social navigation cues for a geographic map service are presented. Results show significantly improved performance for participants who interacted with the map when the visual footprints of previous users were visible.  相似文献   
118.
To bring computer vision closer to human vision, we attempt to enable computer to understand the occlusion relationship in an image. In this paper, we propose five low dimensional region-based occlusion cues inspired by the human perception of occlusion. These cues are semantic cue, position cue, compactness cue, shared boundary cue and junction cue. We apply these cues to predict the region-wise occlusion relationship in an image and infer the layer sequence of the image scene. A preference function, trained with samples consisting of these cues, is defined to predict the occlusion relationship in an image. Then we put all the occlusion predictions into the layering algorithm to infer the layer sequence of the image scene.The experiments on rural, artificial and outdoor scene datasets show the effectiveness of our method for occlusion relationship prediction and image scene layering.  相似文献   
119.
Automated separation and classification of touching or overlapping chromosomes in a metaphase image is a critical step in computer-aided chromosome analysis. The advent of the multiplex fluorescence in situ hybridization (M-FISH) technology enables multi-spectral chromosome image with rich spectral information and DAPI image with abundant texture information. This paper presents a fusion classification scheme to improve the segmentation of overlapping and touching chromosomes. First, the texture and spectral information is fused to partition the chromosome cluster into a series of homologous regions. Then a graph-theoretical classification and pairing method is proposed to resolve any remaining ambiguity of the aforementioned separation process. Experiment results demonstrate that the proposed method outperforms conventional multi-spectral classification methods in touching and overlapping chromosome separation.  相似文献   
120.
This work aims to investigate removal efficiency of oxidation and coagulation/flocculation processes, to provide an effective method for the treatment of biologically pre-treated leachate. Leachate containing 985 mg L(-1) COD was treated by using three treatment schemes, i.e. oxidation, coagulation/flocculation and the combined process of coagulation/flocculation followed by oxidation. The application of single oxidation resulted in the effective removal of COD and color up to 80.4 and 83.2%, respectively. However, residual COD values lower than 200 mg L(-1) could only be achieved under intensive experimental conditions (high dosage of Ca(ClO)(2) and prolonged oxidation time). Coagulation/flocculation yielded residual COD values higher than 200 mg L(-1) even at the optimum coagulation conditions. The combined treatment by coagulation/flocculation followed by oxidation yielded final COD lower than 100 mg L(-1) at the following conditions: pre-coagulation with 250 mg L(-1) PFS (poly-ferric sulfate) and over 30-min post-oxidation, or pre-coagulation with 300 mg L(-1) PFS and over 20-min post-oxidation. Hence, pre-coagulation with PFS followed by oxidation with Ca(ClO)(2) was recommended for advanced treatment of biologically treated leachate.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号