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   9000篇
  免费   1181篇
  国内免费   761篇
电工技术   327篇
技术理论   2篇
综合类   922篇
化学工业   267篇
金属工艺   166篇
机械仪表   348篇
建筑科学   905篇
矿业工程   372篇
能源动力   108篇
轻工业   201篇
水利工程   163篇
石油天然气   249篇
武器工业   42篇
无线电   1174篇
一般工业技术   535篇
冶金工业   399篇
原子能技术   33篇
自动化技术   4729篇
  2024年   31篇
  2023年   142篇
  2022年   243篇
  2021年   300篇
  2020年   289篇
  2019年   279篇
  2018年   229篇
  2017年   290篇
  2016年   340篇
  2015年   354篇
  2014年   650篇
  2013年   598篇
  2012年   694篇
  2011年   771篇
  2010年   612篇
  2009年   605篇
  2008年   582篇
  2007年   610篇
  2006年   469篇
  2005年   434篇
  2004年   380篇
  2003年   311篇
  2002年   268篇
  2001年   213篇
  2000年   177篇
  1999年   144篇
  1998年   124篇
  1997年   87篇
  1996年   89篇
  1995年   79篇
  1994年   75篇
  1993年   48篇
  1992年   46篇
  1991年   36篇
  1990年   32篇
  1989年   21篇
  1988年   19篇
  1987年   15篇
  1986年   10篇
  1985年   26篇
  1984年   26篇
  1983年   26篇
  1982年   28篇
  1981年   21篇
  1980年   25篇
  1979年   29篇
  1978年   12篇
  1977年   7篇
  1976年   14篇
  1964年   5篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
To stimulate sustained leadership development, a holistic model is described that incorporates emotional and neuroendocrine aspects of learning, as well as behavioral change. Intentional change theory, developed over 20 years utilizing longitudinal studies of competency development and complexity theory, can expand our impact on leadership development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
992.
Parallel clustering algorithms   总被引:3,自引:0,他引:3  
Clustering techniques play an important role in exploratory pattern analysis, unsupervised learning and image segmentation applications. Many clustering algorithms, both partitional clustering and hierarchical clustering, require intensive computation, even for a modest number of patterns. This paper presents two parallel clustering algorithms. For a clustering problem with N = 2n patterns and M = 2m features, the time complexity of the traditional partitional clustering algorithm on a single processor computer is O(MNK), where K is the number of clusters. The proposed algorithm on anSIMD computer with MN processors has a time complexity O(K(n + m)). The time complexity of the proposed single-link hierarchical clustering algorithm is reduced from O(MN2) of the uniprocessor algorithm to O(nN) with MN processors.  相似文献   
993.
会馆是同乡人在异乡修筑的聚会联络和办事的馆堂,兴起于唐代。天津会馆的兴起在清朝康熙年间。广东会馆是现存装修最精美,规模最大的一座,后成为全国第一家戏剧博物馆。天津广东会馆采用我国传统的砖木结构体系,融合了北方和南方建筑手法,瓦顶和墙体为北方风格,内檐和兴修又具广东潮州建筑的特色,为我国稀有的会馆建筑。会馆的装修,采用重点装饰的处理方法,以木雕为主,辅以砖、石雕刻,无一不精。广东会馆戏楼的伸出式舞台,符合各国现代剧场舞台设计家所追求的效果。  相似文献   
994.
台西盆地构造单元划分探讨   总被引:1,自引:0,他引:1  
首次提出台湾中央山脉(褶皱带)以西与东南沿海间广大地区为统一的台西盆地。前新生代本区与中央山脉为统一的中生代盆地;古新世—始新世演化成东西两个断槽(一个在西带.一个位于中央山脉);渐新世以隆起为主,主要沉积区在中央山脉;中新世拗陷区主要在台湾海峡东侧至台湾麓山带;上新世一第四纪为造山期,台湾岛的滨海平原区为前陆盆地,沉积了巨厚的上新统和第四系。由西向东盆地可分为西部断陷带、中部隆起反转带和东部坳陷带,盆地南北地质差异也较大。  相似文献   
995.
The source and load uncertainties arising from increased applications of renewable energy sources such as wind and photovoltaic energy in the power system have had adverse effects on optimal planning and dispatching. Models for generating typical renewable energy and load scenarios are constructed to reduce such effects and improve the applicability of a planning and optimal dispatching model of power systems with a high proportion of renewable energy. The traditional clustering-based model for representing such scenarios cannot handle high-dimensional time-series data and consequently the feature-related information obtained cannot fully reflect the characteristics of the data. Thus, a deep convolutional embedded clustering model based on multi-head self-attention is proposed. First, a variational mode decomposition model is optimized to reduce the influence of noise-related signals on the feature extraction. The deep features are then extracted from the data using an improved convolutional autoencoder, and the appropriate number of clusters is determined using the elbow method. Following this, the network parameters are optimized based on the sum of losses during reconstruction and clustering. Subsequently, typical scenarios are then generated based on the optimized network model. Finally, the proposed method is evaluated based on data visualization and evaluation metrics. It is shown that the quality of features and the accuracy of clustering can be effectively improved by the proposed scenario generation method.  相似文献   
996.
吕强 《华中建筑》2008,26(5):53-56
随着北京奥运会的临近和全民健身运动的推广,全国各地均在进行不同程度的体育场馆新建、改建、扩建工程,体育建筑设计也逐渐进入更深入的专业化设计领域。该文基于体育场馆的空间特点,简要介绍了一些体育场馆内部常用声学材料的特点及使用。  相似文献   
997.
肖时钧 《燃料与化工》1998,29(5):237-239
通过对66-5F型焦炉在生产中的出现问题的分析,从设计,施工和生产管理等方面提出了改进措施和建议。  相似文献   
998.
MIQR Active Learning on a Continuous Function and a Discontinuous Function   总被引:1,自引:0,他引:1  
Active learning balances the cost of data acquisition against its usefulness for training. We select only those data points which are the most informative about the system being modelled. The MIQR (Maximum Inter-Quartile Range) criterion is defined by computing the inter-quartile range of the outputs of an ensemble of networks, and finding the input parameter values for which this is maximal. This method ensures data selection is not unduly influenced by ‘outliers’, but is principally dependent upon the ‘mainstream’ state of the ensemble. MIQR is more effective and efficient than contending methods1 . The algorithm automatically regulates the training threshold and the network architecture as necessary. We compare active learning methods by applying them to a continuous function and a discontinuous function. Training is more difficult for a discontinuous function than a continuous function, and the volume of data for active learning is substantially less than for passive learning.  相似文献   
999.
Two experiments explored the integration of animated agents into multimedia environments in the context of R. E. Mayer's (2001) cognitive theory of multimedia learning. Experiment 1 was a 3 (agent properties: agent only, agent with gesture, no agent) × 3 (picture features: static picture, sudden onset, animation) design. Agent properties produced no significant effects. Both sudden onset and animation conditions facilitated performance relative to the static-picture condition. In Experiment 2, we explored the effects of printed text, spoken narration, and spoken narration with the printed text, in a multimedia environment that included an agent, to investigate effects of redundancy. The spoken-narration-only condition outperformed the other 2, with no differences between printed text and printed text with spoken narration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
1000.
我国染料工业发展的新特点和面临的新形势   总被引:1,自引:1,他引:0  
章杰 《纺织导报》2005,(8):23-24,26
我国染料工业发展的新特点是:染料新品不断开发;出口持续增长;生产基地转移。我国染料工业发展面临的新形势是:染料进口逐年增多,价格上涨;国际同行间的竞争加剧、绿色壁垒不断升级;能源紧张。文章在分析这些现象的同时指出我国在染料工业发展中需要注意的问题。  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