全文获取类型
收费全文 | 70480篇 |
免费 | 4933篇 |
国内免费 | 2052篇 |
专业分类
电工技术 | 4162篇 |
技术理论 | 2篇 |
综合类 | 6771篇 |
化学工业 | 5537篇 |
金属工艺 | 2208篇 |
机械仪表 | 2597篇 |
建筑科学 | 12792篇 |
矿业工程 | 2318篇 |
能源动力 | 1276篇 |
轻工业 | 14869篇 |
水利工程 | 3723篇 |
石油天然气 | 2755篇 |
武器工业 | 271篇 |
无线电 | 3427篇 |
一般工业技术 | 4159篇 |
冶金工业 | 4640篇 |
原子能技术 | 300篇 |
自动化技术 | 5658篇 |
出版年
2024年 | 368篇 |
2023年 | 967篇 |
2022年 | 1810篇 |
2021年 | 2250篇 |
2020年 | 2206篇 |
2019年 | 1834篇 |
2018年 | 1667篇 |
2017年 | 1918篇 |
2016年 | 2115篇 |
2015年 | 2396篇 |
2014年 | 5041篇 |
2013年 | 4051篇 |
2012年 | 5028篇 |
2011年 | 5366篇 |
2010年 | 4173篇 |
2009年 | 4446篇 |
2008年 | 3849篇 |
2007年 | 4596篇 |
2006年 | 4142篇 |
2005年 | 3411篇 |
2004年 | 2960篇 |
2003年 | 2647篇 |
2002年 | 2337篇 |
2001年 | 1689篇 |
2000年 | 1357篇 |
1999年 | 1080篇 |
1998年 | 727篇 |
1997年 | 571篇 |
1996年 | 472篇 |
1995年 | 409篇 |
1994年 | 303篇 |
1993年 | 227篇 |
1992年 | 205篇 |
1991年 | 137篇 |
1990年 | 100篇 |
1989年 | 96篇 |
1988年 | 72篇 |
1987年 | 67篇 |
1986年 | 53篇 |
1985年 | 44篇 |
1984年 | 37篇 |
1983年 | 32篇 |
1982年 | 25篇 |
1981年 | 11篇 |
1980年 | 25篇 |
1966年 | 12篇 |
1964年 | 16篇 |
1959年 | 12篇 |
1957年 | 10篇 |
1955年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
132.
133.
介绍了太钢板坯连铸水处理系统的工艺流程,分析了连铸浊环水水质存在的问题。通过对冷却塔部分、铁皮坑、水泵调速等改造,以及选用新的水质稳定剂,使水质明显好转。 相似文献
134.
ANOM(均值分析)是一种有效的质量工具,可以用来分析实验因素对输出的影响是否显著。可以应用于单因子,双因子的实验设计,无论是计量值数据,还是计数值数据,ANOM检验异常值的能力都很强,介绍了ANOM的基本分析过程,对ANOM和ANOVA进行了检验异常值灵敏度大小的比较,同时给出了实例。 相似文献
135.
葡北3-12注气井位于吐哈盆地葡北构造带中断葡北1号构造.井深为3610m。针对该区块地层承压能力低,易漏失,油气水窜严重,常规固井方法无法满足固井要求的问题,该井采用三段三凝制、常规水泥浆和泡沫水泥浆体系固井,并采用重钻井液顶替技术.降低施工压力。该技术能保证固井候凝过程中井底压力平衡,施工安全。现场应用表明,采用常规水泥浆和泡沫水泥浆固井技术.提高了低压易漏井、长封固井段的固井质量,解决了水泥返高不足的问题;并通过一次常规固井工艺实现了全井封固,简化了施工工艺,节约了成本,经济效益和社会效益十分显著。该井封固优质段累计达2600m,优质率达85%,固井结果良好。 相似文献
136.
介绍了唐钢第一炼铁厂近几年来围绕提高烧结矿质量 ,满足高炉冶炼需求所做的大量工作及成效 ,并提出了今后的打算 相似文献
137.
介绍了公路路面工程质量控制要点 ,从路面的平整度、建立健全质量保证体系等方面进行了论述 ,指出强化工程监理、加大监督力度和提高人员素质是确保工程质量的有效途径 相似文献
138.
139.
后浇带质量控制的措施 总被引:1,自引:0,他引:1
后浇带起着超长建筑的温度伸缩、高层建筑高层部分与裙房间沉降缝的作用,已普遍采用,但有些工程由于施工不当,设了后浇带起不到应有作用,本文就施工中如何采取有效措施,对后浇带的质量进行控制,作了探讨,以期能真正发挥后浇带的作用。 相似文献
140.
The IEEE 802.11e medium access control (MAC) layer protocol is an emerging standard to support quality of service (QoS) in
802.11 wireless networks. Some recent work shows that the 802.11e hybrid coordination function (HCF) can improve significantly
the QoS support in 802.11 networks. A simple HCF referenced scheduler has been proposed in the 802.11e which takes into account
the QoS requirements of flows and allocates time to stations on the basis of the mean sending rate. As we show in this paper,
this HCF referenced scheduling algorithm is only efficient and works well for flows with strict constant bit rate (CBR) characteristics.
However, a lot of real-time applications, such as videoconferencing, have some variations in their packet sizes, sending rates
or even have variable bit rate (VBR) characteristics. In this paper we propose FHCF, a simple and efficient scheduling algorithm
for 802.11e that aims to be fair for both CBR and VBR flows. FHCF uses queue length estimations to tune its time allocation
to mobile stations. We present analytical model evaluations and a set of simulations results, and provide performance comparisons
with the 802.11e HCF referenced scheduler. Our performance study indicates that FHCF provides good fairness while supporting
bandwidth and delay requirements for a large range of network loads.
Pierre Ansel received a multidisciplinary in-depth scientific training in different fields such as Pure and Applied Mathematics, Physics,
Mechanics, Computer Science and Economics from the Ecole Polytechnique, Palaiseau, France. Then, he joined the Ecole Nationale
Superieure des Telecommunications, Paris, France in 2005 where he went further into electronics, databases, computer network
security and high speed networks. He received a multidisciplinary master of sciences degree and an additional master of sciences
degree in telecommunications in 2005. He did a summer internship in 2003 in INRIA, Sophia Antipolis, France where he worked
on the Quality of Service in 802.11 networks at Planete Group, France. Then in 2004, he joined France Telecom R&D, Issy-les-Moulineaux,
France to work on Intranet Security issues. He designed a WiFi security supervision architecture based on WiFi Intrusion Detection
Sensors. He is currently a French civil servant and belongs to the French Telecommunications Corps.
Qiang Ni received the B.Eng., M.Sc. and Ph.D. degrees from Hua Zhong University of Science and Technology (HUST), Wuhan City, China
in 1993, 1996 and 1999 respectively. He is currently a faculty member in the Electronic and Computer Engineering Division,School
of Engineering and Design, Brunel University, West London, U.K. Between 2004 and 2005 he was a Senior Researcher at the Hamilton
Institute, National University of Ireland, Maynooth. From 1999 to 2001, he was a post-doctoral research fellow in the multimedia
and wireless communication laboratory, HUST, China. He visited and conducted research at the wireless and networking group
of Microsoft Research Asia Lab during the year of 2000. From Sept. 2001 until may 2004, he was a research staff member at
the Planète group of INRIA Sophia Antipolis France. Since 2002, he has been active as a voting member at the IEEE 802.11 wireless
LAN standard working group. His current research interests include communication protocol design and performance analysis
for wireless networks, cross-layer optimizations, vertical handover and mobility management in mobile wireless networks, and
adaptive multimedia transmission over hybrid wired/wireless networks. He has authored /co-authored over 40 international journal/conference
papers, book chapters, and standard drafts in this field. He is a member of IEEE. E-mail: Qiang.Ni@ieee.org
Thierry Turletti received the M.S. (1990) and the Ph.D. (1995) degrees in computer science both from the University of Nice – Sophia Antipolis,
France. He has done his PhD studies in the RODEO group at INRIA Sophia Antipolis. During the year 1995–96, he was a postdoctoral
fellow in the Telemedia, Networks and Systems group at LCS, MIT. He is currently a research scientist at the Planete group
at INRIA Sophia Antipolis. His research interests include multimedia applications, congestion control and wireless networking.
Dr. Turletti currently serves on the Editorial Board of Wireless Communications and Mobile Computing. 相似文献