全文获取类型
收费全文 | 9978篇 |
免费 | 656篇 |
国内免费 | 701篇 |
专业分类
电工技术 | 630篇 |
技术理论 | 4篇 |
综合类 | 973篇 |
化学工业 | 191篇 |
金属工艺 | 88篇 |
机械仪表 | 390篇 |
建筑科学 | 353篇 |
矿业工程 | 195篇 |
能源动力 | 77篇 |
轻工业 | 137篇 |
水利工程 | 90篇 |
石油天然气 | 133篇 |
武器工业 | 24篇 |
无线电 | 2438篇 |
一般工业技术 | 395篇 |
冶金工业 | 297篇 |
原子能技术 | 10篇 |
自动化技术 | 4910篇 |
出版年
2024年 | 30篇 |
2023年 | 147篇 |
2022年 | 275篇 |
2021年 | 410篇 |
2020年 | 442篇 |
2019年 | 232篇 |
2018年 | 204篇 |
2017年 | 299篇 |
2016年 | 335篇 |
2015年 | 333篇 |
2014年 | 657篇 |
2013年 | 650篇 |
2012年 | 734篇 |
2011年 | 703篇 |
2010年 | 471篇 |
2009年 | 359篇 |
2008年 | 419篇 |
2007年 | 491篇 |
2006年 | 483篇 |
2005年 | 493篇 |
2004年 | 484篇 |
2003年 | 542篇 |
2002年 | 546篇 |
2001年 | 521篇 |
2000年 | 467篇 |
1999年 | 306篇 |
1998年 | 159篇 |
1997年 | 58篇 |
1996年 | 35篇 |
1995年 | 18篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1991年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1981年 | 3篇 |
1966年 | 1篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1960年 | 3篇 |
1959年 | 1篇 |
1955年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Riley William T.; Schumann Mary F.; Forman-Hoffman Valerie L.; Mihm Patricia; Applegate Bradford W.; Asif Ofer 《Canadian Metallurgical Quarterly》2007,38(1):44
Increased adoption of empirically supported treatments (ESTs) has been hindered in part by inadequate and inconvenient access to EST information and training. To improve diffusion of ESTs, the authors developed a Web application to provide practitioners with concise information by disorder on ESTs. The resulting site, therapyadvisor.com, was evaluated by 239 practicing psychologists to assess the usefulness of the site and explore possible interactions of EST attitudes on ratings of usefulness and impact. Two thirds of participants indicated using ESTs in practice, and limited time and resources were cited as primary barriers to EST adoption. The Web application was rated positively by most participants and was reported to increase awareness of and commitment to try ESTs among approximately 60% of participants. The results of this project support the feasibility of a Web application to increase diffusion and promote further adoption of ESTs. Technological and e-learning advances are promising directions for encouraging the adoption of ESTs specifically and evidence-based practice generally, particularly among busy practitioners who have inadequate time and resources for more traditional forms of dissemination and training. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
32.
该文首先简要介绍目前IP网上的移动管理方案MobileIP,然后重点分析讨论对MobileIP进行的改进和扩展,最后提出一种基于MobileIP的适于未来全IP网络的分层移动管理结构。 相似文献
33.
34.
Using the Internet, “public” computing grids can be assembled using “volunteered” PCs. To achieve this, volunteers download and install a software application capable of sensing periods of low local processor activity. During such times, this program on the local PC downloads and processes a subset of the project's data. At the completion of processing, the results are uploaded to the project and the cycle repeats. 相似文献
35.
The objective, strategy, and implementation details of a new undergraduate course, Internet-based Instrumentation and Control, are presented. The course has a companion laboratory that is supported by the National Science Foundation and industry. The combination is offered to senior-level undergraduate engineering students interested in sensing, instrumentation, control, and web programming that want to learn more about the integration of these technologies for solving real-world engineering problems. The course will also be offered to gifted high school seniors with similar interests and can serve as a vehicle to attract them to engineering disciplines. Preliminary assessment of the first offering of the course is encouraging and has shown that the course has achieved success in helping students understand concepts and master basic technologies for developing Internet-based automatic systems. 相似文献
36.
Xiaoming Zhou Martin Jacobsson Henk Uijterwaal Piet Van Mieghem 《International Journal of Communication Systems》2008,21(6):643-663
Although packet delay and loss are two important parameters of the Internet performance, to the best of our knowledge, the evolution of large‐scale IPv6 delay and loss performance has previously not been studied. In this paper, we analyze more than 600 end‐to‐end IPv6 paths between about 26 testboxes of RIPE Network Coordination Centre over two years, and compare the delay and loss performance over time with their IPv4 counterparts. We present and discuss the measurement methodologies and show that IPv6 paths have a higher delay and loss than their IPv4 counterparts. The main reason for the worse performance stems from IPv6‐in‐IPv4 tunnels rather than from native IPv6 paths and such tunnels are still widely used today. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
37.
互联网下会计信息系统内部控制研究 总被引:1,自引:0,他引:1
王腊梅 《武汉理工大学学报(信息与管理工程版)》2004,26(4):85-87,95
网络会计给企业带来利益的同时 ,也给企业内部控制带来新问题。讨论了建立适应互联网环境下会计信息系统的内部控制 ,其措施应基于企业内部和外部的组织与管理、系统开发及网络系统安全控制等方面的问题 相似文献
38.
为了实现异步电机现场控制与上层管理的无缝集成,提出在通用变频器一异步电动机调速系统的基础上,采用基于ARM7TDMI核的微控制器和以太网控制芯片,实现异步电机的网络化控制。详细介绍了该系统的体系结构设计方案。 相似文献
39.
The Role of Network Topologies in the Optical Core of IP-over-WDM Networks with Static Wavelength Routing 总被引:3,自引:0,他引:3
Freire Mário M. Rodrigues Joel J.P.C. Coelho Rui M.F. 《Telecommunication Systems》2003,24(2-4):111-122
In this paper, we present a performance analysis of network topologies for the optical core of IP-over-WDM networks with static wavelength routing. The performance analysis is focused on regular degree four topologies, and, for comparison purposes, degree three topologies are also considered. It is shown that the increase of the nodal degree from three (degree three topology with smallest diameter) to four (degree four topology with smallest diameter) improves the network performance if a larger number of wavelengths per link is available. However, the influence of wavelength interchange on the nodal degree gain is small. The performance of regular degree four topologies with smallest diameter is also compared with the performance of mesh–torus topologies (which are also degree four topologies), and it is shown that the blocking probability of degree four topologies with smallest diameter is about two orders of magnitude lower than the blocking probability of mesh–torus topologies. It is also presented a performance comparison of WDM-based networks with nodal degrees ranging from two to five and it is shown that the increase of the nodal degree from two to three leads to high nodal degree gains, while de increase of the nodal degree from four to five leads to low nodal degree gains. These results show that degree three and degree four topologies are very attractive for use in the optical core of IP-over-WDM networks. 相似文献
40.