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991.
992.
随着云计算技术的快速发展和更广泛应用,云计算的潜在风险越来越受到关注。文章介绍了云计算的应用现状及重要特点,分析了云计算存在的风险,从技术的角度对云计算的潜在风险进行分析。 相似文献
993.
Alireza Montazeri Behzad Akbari Mohammed Ghanbari 《Peer-to-Peer Networking and Applications》2012,5(3):257-278
P2P video streaming networks are found as a scalable solution and an alternative for traditional client–server based video
streaming over the Internet. One of the significant issues affecting the success of any P2P streaming network is cooperation
between peers. Practical observations have proved the prevalence of free riders in P2P networks that degrade their performance.
To solve this problem, using incentive mechanisms, which encourage peers to contribute more in the network, is necessary.
In this paper, we designed and proposed a distributed and scalable incentive mechanism for mesh based P2P video streaming
networks. In the proposed approach the contribution of the peers is measured and maintained in a distributed fashion. Furthermore,
we proposed an incentive sending side scheduler in which peers are served based on their contribution in the network. Our
simulation evaluations show the efficiency of the proposed approach in improving the overall perceived video quality by the
non-free rider nodes and consequently in the whole network. 相似文献
994.
Mohammed Hawa Jamal S. Rahhal Dia I. Abu-Al-Nadi 《Peer-to-Peer Networking and Applications》2012,5(3):279-291
Peer-to-Peer (P2P) traffic has increased rapidly over the past few years, with file sharing providing the main drive behind
such traffic. In this work we perform a measurement study of the content shared over the popular BitTorrent P2P file sharing
network. We mathematically model the file size distributions of shared files after categorizing them into Audio, Video, Archive
and CD image classes. For each of these categories we look into the most popular shared file formats and investigate their
file size statistics. This provides an important milestone to building a realistic simulation framework for P2P systems, and
for future analytical modeling of P2P networks. 相似文献
995.
D. Cenk Erdil 《Peer-to-Peer Networking and Applications》2012,5(3):219-230
Resource scheduling in large-scale distributed systems, such as grids and clouds, is difficult due to the size, dynamism,
and volatility of resources. These resources are eclectic and autonomous, and may exhibit different usage policies, levels
of participation, capabilities, local load, and reliability. Moreover, applications are likely to exhibit various patterns
and levels, and distributed resources may organize into various different overlay topologies for information and query dissemination.
Researchers have proposed a wide variety of approaches and policies for mapping offered load onto resources and for solving
the various component parts of the scheduling problem. However, production clouds and grids may be underutilized, and may
not exhibit the load to effectively characterize all of the scheduling system inputs. The composition of large-scale systems
is also changing, potentially to include more individual and peer-to-peer resources. These factors will influence the effectiveness
of proposed scheduling solutions. Therefore, a simulation environment is necessary to study different approaches under different
scenarios, especially those that are expected, but that are not currently characteristic of existing systems. This article
describes a general-purpose peer-to-peer simulation environment that allows a wide variety of parameters, protocols, strategies
and policies to be varied and studied. To provide a proof of concept, utilization of the simulation environment is presented
in a large-scale distributed system problem that includes a core model and related mechanisms. In particular, this article
presents a definition and possible peer-to-peer solutions for the large-scale scheduling problem. Moreover, this article describes
a general simulation model, some policies that can be varied, an implementation, and some sample results. 相似文献
996.
A super-peer semantic network defines the semantic groups that client peers and their super peers use to connect with each
other according to the semantic similarity of shared documents in peers. This will result in a query that can be evaluated
locally thus reducing query process time and the amount of communication required to obtain related data. In this study, new
algorithms are proposed to arrange shared documents in peers into hierarchical cluster tree structures, and links will be
set up to connect semantically related super peers. During query evaluation, only related peers will be searched thus the
complexity of computing is significantly reduced. Consideration is also given to automatically deciding the threshold for
clustering and the construction and other essential operations for hierarchical cluster trees. The experiment results illustrate
the features of the approach developed in this study. 相似文献
997.
郭崎 《计算机辅助设计与图形学学报》2012,24(5):690-698
如何生成高质量的验证激励是功能验证中的核心问题之一.随着功能验证的不断进行,验证激励的有效性也随之降低.为了提高验证激励的质量,提出一种在线筛选技术来处理验证激励.该技术采用单分类支持向量机来在线地构建分类器,以对新生成的验证激励是否冗余进行预测,如果是冗余的,则不进入仿真阶段进行仿真.在此基础上,进一步提出指令序列核函数来衡量不同指令序列的相似程度.实验结果表明,与约束随机生成技术相比,文中技术可以减少约83%的验证激励及79%的验证时间. 相似文献
998.
为了提高肝癌手术治疗计划的可靠性,在利用腹部CT图像数据进行肝脏三维重建的基础上,实现了任意角度对虚拟肝脏进行平面切割和切割面结构的显示;通过构造可以调节大小、位置的球体模型,实现了球体切除;通过在肝脏三维模型表面上勾画不规则封闭区域,实现了任意曲面肝脏切除;并依据肝内血管结构进行肝段划分,实现了解剖性肝段切除.临床实验结果表明,文中所述的技术能够满足虚拟手术的需求,有利于医生制定安全可靠的术前计划,提高手术成功率. 相似文献
999.
1000.
分层思想在JSP技术的开发过程中的优点是层次清楚,这有利于不同程序员分式开发,从而提高效率;但是在应用每一层相关类的时候需要实例化,这会增加系统开销。采用工厂模式在开发过程中向程序员提供一个"工厂"供程序员选择"零件",可以减少实例化次数。工厂开发模式在JSP+tomcat的开发中,可结合分层思想,按照不同的层次进行开发,同时也可独立出公共模块切入到其他模块中,有效地避免了代码重复,提高了开发效率。 相似文献