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   4407篇
  免费   360篇
  国内免费   275篇
电工技术   218篇
综合类   364篇
化学工业   19篇
金属工艺   12篇
机械仪表   128篇
建筑科学   306篇
矿业工程   50篇
能源动力   76篇
轻工业   24篇
水利工程   81篇
石油天然气   12篇
武器工业   10篇
无线电   814篇
一般工业技术   165篇
冶金工业   317篇
原子能技术   5篇
自动化技术   2441篇
  2024年   15篇
  2023年   32篇
  2022年   64篇
  2021年   76篇
  2020年   120篇
  2019年   61篇
  2018年   87篇
  2017年   116篇
  2016年   118篇
  2015年   156篇
  2014年   272篇
  2013年   321篇
  2012年   288篇
  2011年   327篇
  2010年   299篇
  2009年   301篇
  2008年   429篇
  2007年   419篇
  2006年   329篇
  2005年   290篇
  2004年   225篇
  2003年   156篇
  2002年   96篇
  2001年   70篇
  2000年   65篇
  1999年   50篇
  1998年   36篇
  1997年   28篇
  1996年   27篇
  1995年   31篇
  1994年   20篇
  1993年   7篇
  1992年   5篇
  1991年   7篇
  1990年   9篇
  1989年   7篇
  1988年   6篇
  1987年   4篇
  1986年   7篇
  1984年   7篇
  1982年   7篇
  1981年   4篇
  1980年   4篇
  1979年   3篇
  1973年   4篇
  1966年   5篇
  1959年   2篇
  1956年   6篇
  1955年   6篇
  1954年   2篇
排序方式: 共有5042条查询结果,搜索用时 0 毫秒
81.
区分服务网络中SCTP协议的改进   总被引:1,自引:0,他引:1       下载免费PDF全文
刘辉  唐扬 《计算机工程》2009,35(6):113-115
针对双窗口算法难以判断包丢弃类型的问题,提出一种新的包丢弃类型判断方法,对SCTP协议的确认块进行扩展,从确认块中获取包丢弃类型信息。在NS2上进行仿真实验,实验结果表明,改进后的SCTP协议在吞吐率方面有显著提高。  相似文献   
82.
Using the data collected from the online banking users in Taiwan, we build a hierarchical model of e-banking service quality and investigate the relationships among e-service quality, trust, satisfaction, loyalty, and brand equity. Moreover, the simultaneous equations system approach is also applied to transfer the traditional satisfaction-loyalty path into the simultaneous relationships between trust and loyalty, and between satisfaction and loyalty. As the structural form coefficients demonstrate the direct relations between our research constructs, the reduced form estimates further disclose the total impacts of the quality of e-banking service on trust, satisfaction, loyalty, and brand equity, respectively. The results indicate that the perceived quality formed through interaction with an online banking service positively affects customer trust and satisfaction, which in turn influence loyalty and brand equity. The significant simultaneous relationships between trust and loyalty, and between satisfaction and loyalty, are confirmed by our data, implying that these relationships must be determined simultaneously, rather than sequentially.  相似文献   
83.
Integration of models requires linking models which can be developed using different tools, methodologies, and assumptions. We performed a literature review with the aim of improving our understanding of model integration process, and also presenting better strategies for building integrated modeling systems. We identified five different phases to characterize integration process: pre-integration assessment, preparation of models for integration, orchestration of models during simulation, data interoperability, and testing. Commonly, there is little reuse of existing frameworks beyond the development teams and not much sharing of science components across frameworks. We believe this must change to enable researchers and assessors to form complex workflows that leverage the current environmental science available. In this paper, we characterize the model integration process and compare integration practices of different groups. We highlight key strategies, features, standards, and practices that can be employed by developers to increase reuse and interoperability of science software components and systems.  相似文献   
84.
车联网作为物联网在汽车行业的应用领域之一,是汽车智能化的重要发展方向,介绍基于位置的服务,并详细描述该服务的一个应用实例:一套完整的基于位置服务的车辆调度管理系统;介绍该系统的部分功能模块的详细功能以及该系统在实践中的应用,说明该系统应用前景和社会效益。  相似文献   
85.
随着云计算的普及和越来越多的云计算产品投入使用,频频爆发的安全事件也呈现在人们眼前,安全问题更加重要并且已经严重制约了其发展。首先对云计算的概念和发展进行了概述,分析了云计算面临的安全威胁,对提出了应对风险的云计算安全防范关键技术,最后对云计算环境下少数民族文化知识服务进行了探讨。  相似文献   
86.
The increasing volume of eGovernment‐related services is demanding new approaches for service integration and interoperability in this domain. Semantic web (SW) technologies and applications can leverage the potential of eGovernment service integration and discovery, thus tackling the problems of semantic heterogeneity characterizing eGovernment information sources and the different levels of interoperability. eGovernment services will therefore be semantically described in the foreseeable future. In an environment with semantically annotated services, software agents are essential as the entities responsible for exploiting the semantic content in order to automate some tasks, and so enhance the user's experience. In this paper, we present a framework that provides a seamless integration of semantic web services and intelligent agents technologies by making use of ontologies to facilitate their interoperation. The proposed framework can assist in the development of powerful and flexible distributed systems in complex, dynamic, heterogeneous, unpredictable and open environments. Our approach is backed up by a proof‐of‐concept implementation, where the breakthrough of integrating disparate eGovernment services has been tested.  相似文献   
87.
Metaphors are often used to provide the user with a mental model to ease the use of computers. An example of such a metaphor is the commonly used “Desktop Metaphor”. Metaphors also can be used to ease context-aware information access for the users of mobile information systems. In this paper we present a taxonomy that allows the categorisation of such metaphors. Furthermore, we give an overview of existing metaphors and their implementations. After introducing some new metaphors we conclude our considerations with a classification of new and existing metaphors using our taxonomy.  相似文献   
88.
The opportunities for context-aware computing are fast expanding. Computing systems can be made aware of their environment by monitoring attributes such as their current location, the current time, the weather, or nearby equipment and users. Context-aware computing often involves retrieval of information: it introduces a new aspect to technologies for information delivery; currently these technologies are based mainly on contemporary approaches to information retrieval and information filtering. In this paper, we consider how the closely related, but distinct, topics of information retrieval and information filtering relate to context-aware retrieval. Our thesis is that context-aware retrieval is as yet a sparsely researched and sparsely understood area, and we aim in this paper to make a start towards remedying this.  相似文献   
89.
两种因特网服务模型的比较研究   总被引:5,自引:0,他引:5  
未来的计算机网络将是一种能够提供多种有同服务,以支持多种不同应用需求,有着集成服务(integrated services)支持能力的网络.这种网络是通过在统一的分组交换网络上实现各种不同的服务性能保证机制来构造的.针对止目前广泛研究的两种不同因特网服务模型进行比较研究,分析它们各自组成部件的功能入作用,比较两者之间存在的内在联系,从而进一步提出了一种融合两者优点的组合扩展模型,并以此为基础提出了  相似文献   
90.
电子商务中有一类应用既使用了固定终端又使用了移动终端,它们共享同一数据库服务器,与之进行数据的交换。针对这种复杂的应用系统,提出了一种便捷完整的解决方案,并探讨了实现这一方案用到的移动数据库、数据同步等相关技术问题。  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