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   20246篇
  免费   1125篇
  国内免费   1567篇
电工技术   1773篇
综合类   1794篇
化学工业   111篇
金属工艺   104篇
机械仪表   729篇
建筑科学   1461篇
矿业工程   716篇
能源动力   262篇
轻工业   135篇
水利工程   836篇
石油天然气   94篇
武器工业   82篇
无线电   1899篇
一般工业技术   288篇
冶金工业   137篇
原子能技术   40篇
自动化技术   12477篇
  2025年   40篇
  2024年   96篇
  2023年   83篇
  2022年   145篇
  2021年   207篇
  2020年   280篇
  2019年   209篇
  2018年   223篇
  2017年   279篇
  2016年   410篇
  2015年   485篇
  2014年   968篇
  2013年   925篇
  2012年   1244篇
  2011年   1533篇
  2010年   1497篇
  2009年   1681篇
  2008年   1861篇
  2007年   2014篇
  2006年   1965篇
  2005年   1680篇
  2004年   1359篇
  2003年   1182篇
  2002年   873篇
  2001年   666篇
  2000年   489篇
  1999年   261篇
  1998年   128篇
  1997年   59篇
  1996年   34篇
  1995年   19篇
  1994年   9篇
  1993年   8篇
  1992年   7篇
  1991年   10篇
  1990年   2篇
  1989年   4篇
  1987年   1篇
  1986年   1篇
  1979年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
林虹虹 《现代计算机》2011,(10):106-109
目前的远程教学中主要依赖的信息共享、个体学习、有限交互的模式,已经不能满足学习者对学习质量越来越高的期望。在此,提出一个协作学习模型。这种协作方式可以使学生在信息交流的过程中,更好地了解他人的观点、方法和建议,促进自己的学习。同时,这种模型也为基于Web的信息交流提供新的协作方式。  相似文献   
3.
基于智能客户端的巡检系统设计与实现   总被引:1,自引:0,他引:1  
孙晖 《计算机与现代化》2011,(2):157-159,163
针对健康检查中心医生外出进行健康检查作业时,健康检查系统无法离线使用的问题,本文应用智能客户端技术构建巡检系统。该巡检系统可以在离线状态完成健检系统功能,待系统连线以后,通过调用Web Service访问健康检查中心数据库进行数据上传和下载。对系统进行总体设计,给出体系结构图,并且详细介绍相关技术及实现。  相似文献   
4.
地图的显示和基于地图的操作是地理信息系统(GIS)开发的基础,介绍一种基于ASPMAP控件开发Web地图显示程序,具有简单、方便、实用和功能强大的特点。  相似文献   
5.
Web proxy caches are used to reduce the strain of contemporary web traffic on web servers and network bandwidth providers. In this research, a novel approach to web proxy cache replacement which utilizes neural networks for replacement decisions is developed and analyzed. Neural networks are trained to classify cacheable objects from real world data sets using information known to be important in web proxy caching, such as frequency and recency. Correct classification ratios between 0.85 and 0.88 are obtained both for data used for training and data not used for training. Our approach is compared with Least Recently Used (LRU), Least Frequently Used (LFU) and the optimal case which always rates an object with the number of future requests. Performance is evaluated in simulation for various neural network structures and cache conditions. The final neural networks achieve hit rates that are 86.60% of the optimal in the worst case and 100% of the optimal in the best case. Byte-hit rates are 93.36% of the optimal in the worst case and 99.92% of the optimal in the best case. We examine the input-to-output mappings of individual neural networks and analyze the resulting caching strategy with respect to specific cache conditions.  相似文献   
6.
胡悦嘉 《网络与信息》2009,23(10):14-15
浏览器以B/S的访问方式可以有效地提高用户访问速度,解决远程和移动办公效率问题.中国海油对Domino办公平台进行了Web应用改造.本文介绍了Web办公信息门户设计,对Web办公信息门户的总体框架、动态站点生成工具Indi.SiteMaster、Web系统身份验证接13和管理程序、应用模块的Web改造、Web首页设计做了阐述,并简述了办公平台Web应用改造的效果、存在的问题与展望.  相似文献   
7.
Recent natural disasters indicate that modern technologies for environmental monitoring, modeling, and forecasting are not well integrated with cross-level social responses in many hazard-management systems. This research addresses this problem through a Java-based multi-agent prototype system, GeoAgent-based Knowledge System (GeoAgentKS). This system allows: (1) computer representation of institutional regulations and behavioral rules used by multiple social institutions and individuals in cross-level human–environment interactions, (2) integration of this representation with scientific modeling of dynamic hazard development, and (3) application of automated reasoning that suggests to users the appropriate actions for supporting cooperative social responses. This paper demonstrates the software architecture of GeoAgentKS and presents such an integrated approach by modeling the drought management processes in Central Pennsylvania, USA. The results show that it is possible to use GeoAgentKS to represent multilevel human–environment interactions and to use those interactions as input to decision making in hazard management.  相似文献   
8.
随着网络课程数量的日益增多,在网络课程制作中使用FlashPaper技术也越来越常见。文章首先介绍了FlahshPaper软件的工作原理的,其次重点介绍了该软件的使用方法和步骤,并总结出了使用FlashPaper技术在网络课程页面呈现中所体现出的优越性。  相似文献   
9.
“Global Interoperability Using Semantics, Standards, Science and Technology” is a concept that is predicated on the assumption that the semantic integration, frameworks and standards that support information exchange, and advances in science and technology can enable information-systems interoperability for many diverse users. This paper recommends technologies and approaches for enabling interoperability across a wide spectrum of political, geographical, and organizational levels, e.g. coalition, federal, state, tribal, regional, non government, and private. These recommendations represent steps toward the goal of the Semantic Web, where computers understand information on web sites through knowledge representations, agents, and ontologies.  相似文献   
10.
Suitability evaluation of urban construction land based on geo-environmental factors is the process of determining the fitness of a given tract of land for construction. This process involves a consideration of the geomorphology, geology, engineering geology, geological hazards, and other geological factors and is the basis of urban construction land planning and management. With the support of Geographic Information Systems (GIS), grid analysis, and geo-spatial analysis techniques, four factor groups comprising nine separate subfactors of geo-environmental attributes were selected to be used in the evaluation of the suitability level for construction land in Hangzhou. This was based on K-means clustering and back-propagation (BP) neural network methods due to their advantages in fast computing, unique adaptive capacity, and self-organization. Simultaneously, the evaluation results based on K-means clustering and BP neural network were compared and analyzed, and the accuracy evaluation was set. The results showed that the geo-environmental suitability evaluation results of construction land based on K-means clustering and BP neural network were similar in terms of the distribution and scale of construction land suitability level. At the same time, the results of the two evaluation methods were consistent with the variability in suitability level, engineering geology, and hydrogeology of Hangzhou. The results also showed that the real advantage of the methods proposed in this paper lies in their capacity to streamline the mapping process and to ensure that the results are consistent throughout. The suitability level of the urban construction land based on the geo-environment in Hangzhou was divided into four construction sites: land for building super high-rise and high-rise buildings, land for building multistorey buildings, land for low-rise buildings, and nonbuilding land. The results of the suitability evaluation for each category will provide a scientific basis for decision-making in urban development in Hangzhou.  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