全文获取类型
收费全文 | 3886篇 |
免费 | 201篇 |
国内免费 | 221篇 |
专业分类
电工技术 | 157篇 |
综合类 | 196篇 |
化学工业 | 205篇 |
金属工艺 | 201篇 |
机械仪表 | 631篇 |
建筑科学 | 110篇 |
矿业工程 | 27篇 |
能源动力 | 117篇 |
轻工业 | 40篇 |
水利工程 | 27篇 |
石油天然气 | 24篇 |
武器工业 | 37篇 |
无线电 | 508篇 |
一般工业技术 | 350篇 |
冶金工业 | 40篇 |
原子能技术 | 6篇 |
自动化技术 | 1632篇 |
出版年
2024年 | 5篇 |
2023年 | 44篇 |
2022年 | 66篇 |
2021年 | 103篇 |
2020年 | 70篇 |
2019年 | 71篇 |
2018年 | 54篇 |
2017年 | 105篇 |
2016年 | 84篇 |
2015年 | 114篇 |
2014年 | 166篇 |
2013年 | 209篇 |
2012年 | 234篇 |
2011年 | 299篇 |
2010年 | 240篇 |
2009年 | 268篇 |
2008年 | 264篇 |
2007年 | 304篇 |
2006年 | 277篇 |
2005年 | 242篇 |
2004年 | 202篇 |
2003年 | 155篇 |
2002年 | 144篇 |
2001年 | 97篇 |
2000年 | 70篇 |
1999年 | 86篇 |
1998年 | 89篇 |
1997年 | 44篇 |
1996年 | 56篇 |
1995年 | 41篇 |
1994年 | 25篇 |
1993年 | 15篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有4308条查询结果,搜索用时 15 毫秒
81.
《Organic Electronics》2014,15(7):1317-1323
Aligned single-crystalline organic nanowires (NWs) show promising applications in flexible and stretchable electronics, while the use of pre-existing aligned techniques and well-developed photolithography techniques are impeded by the large incompatibility with organic materials and flexible substrates. In this work, aligned copper phthalocyanine (CuPc) organic NWs were grown on flexible and transparent poly(dimethylsiloxane) (PDMS) substrate via a grating-assisted growth approach. Furthermore, a simple yet efficient etching-assisted transfer printing (ETP) method was used to achieve CuPc NW array-based flexible top-gate organic field-effect transistors (OFETs) with a high mobility up to 2.0 cm2 V−1 s−1, a small operating voltage within ±10 V, a high on/off ratio >104, and excellent bend stability with bending radius down to 3 mm. It is expected that the high-performance organic NW array-based top-gate OFETs with exceeding bend stability will have important applications in future flexible electronics. 相似文献
82.
Shuqiang Zhang Lei Shi Chaitanya S.K. Vadrevu Biswanath Mukherjee 《Optical Switching and Networking》2013,10(4):291-300
Network virtualization can eradicate the ossification of the Internet and stimulate innovation of new network architectures and applications. Optical networks are ideal substrates for provisioning high-bandwidth virtual-network services. In this study, we investigate the problem of network virtualization over both WDM and flexible-grid optical networks by formulating the problems as mixed integer linear programs (MILP). Two heuristics, namely MaxMapping and MinMapping, are developed for each kind of network to solve the problem quickly but suboptimally. Numerical examples show that MinMapping consumes fewer spectrum resources than MaxMapping and performs very close to the optimal results derived by the MILP in both kinds of optical networks, by exploring the opportunities of traffic grooming. Also, it is verified that flexible-grid optical networks can be more spectrum efficient than WDM networks as the substrate for network virtualization. 相似文献
83.
Two waves of technology are dramatically changing daily life: cloud computing and mobile phones. New cloud computing services such as webmail and content rich data search have emerged. However, in order to use these services, a mobile phone must be able to run new applications and handle high network bandwidth. Worldwide, about 3.45 billion mobile phones are low end phones;they have low bandwidth and cannot run new applications. Because of this technology gap, most mobile users are unable to experience cloud computing services with their thumbs. In this paper, a novel platform, Thumb-in-Cloud, is proposed to bridge this gap.Thumb-in-Cloud consists of two subsystems: Thumb-Machine and Thumb-Gateways. Thumb-Machine is a virtual machine built into a low end phone to enable it to run new applications. Thumb-Gateways can tailor cloud computing services by reformatting and compressing the service to fit the phone' s profile. 相似文献
84.
随着全球的LCM制造业的迅速发展,LCM专用设备已日益受到制造商的高度重视.介绍了双工位FOG邦定机的主要特点和技术指标,分析了设备的机械结构以及控制系统的硬件和软件的设计. 相似文献
85.
The adhesion strength of a Cu/Ni-Cr/polyimide flexible copper clad laminate (FCCL), was evaluated according to the thickness of the Ni-Cr (Ni:Cr = 95:5 ratio) seed layer using the 90° peel test. The changes in the morphology, chemical bonding and adhesion properties were characterized by SEM, AFM and XPS. The peel strength of the FCCL increased with increasing thickness of the Ni-Cr seed layer, due to the increase in the ion bombardment caused by the higher power used in the Ni-Cr sputtering process. This increase in the FCCL peel strength was attributed to the lower proportion of C-N bonds and higher proportion of C-O bonds in the polyimide surface. The adhesion strength between the metal and polyimide was mostly attributed to the chemical interaction between the metal layer and the functional groups of the polyimide. 相似文献
86.
根据网通公司电话银行系统的现状和公司对系统省级集中控制的需求,基于先进的网络应用开发中间件ACE自适配通信环境,设计并实现了网通话费代收系统。 相似文献
87.
针对灵活网格光网络中如何节约转发器与频谱资源的问题,该文研究了多点到多点组播业务的光路环路由机制,提出一种基于距离自适应和有效共享路径感知的光疏导方法。通过设计一种基于距离自适应的预处理机制,该疏导方法能根据业务成员节点的分布特点和距离自适应准则灵活地为业务构建光路环;在路由与频谱分配阶段,该疏导方法通过构造一个面向光疏导的业务决策矩阵和一个优先调度向量,将业务疏导到与当前业务具有有效共享路径最多的已路由业务上,并优先分配所需的频谱空间以提高光疏导的成功率,实现节约转发器与频谱资源的目的。仿真结果表明,该文提出的光疏导方法可以有效地减少业务消耗的转发器数目和子载波数目。 相似文献
88.
针对机载综合射频开放式系统架构,为了在软件综合层面上实现波形应用软件与具体平台的解耦,设计并实现了一种基于软件通信架构(Software Communication Architecture, SCA)的软件平台及其环境工具,解决了机载平台软件的分布式通信、资源调度管理、系统建模等技术问题,从而实现功能、应用和波形的组件化与动态重构。测试验证与工程应用情况表明,软件平台能够满足机载领域信号、信息处理强实时、高可用的应用需求,可有效提升综合射频系统软件开发质量与集成联试效率。 相似文献
89.
《Mechatronics》2022
A wide range of dangerous and special tasks have witnessed the applications of wall-climbing robots, but they still cannot adapt well torough or sloping walls. This paper proposes a 6-DOF (degree of freedom) humanoid wall-climbing robot (HWCR) based on the principle of negative pressure suction. HWCR has the advantages of flexible adsorption feet, strong adaptability, strong anti-subversion performance, and high friction to the wall. We deduce mechanics formulas and carry out a parametric design of the foot structure so that it can meet the requirement of robot wall climbing. We use Fluent to analyze the flow field of the adsorption foot and determine the motor speed that can provide a reliable adsorption force. Using the D-H matrix to plan gait, we also design a compound cycloid-based foot trajectory to reduce the impact between the HWCR and the wall. Experiments on the uneven wall and sloping wall show that the vehicle can walk with an ideal gait, and the resistance value of the servo on each joint is much lower than the critical value, which ensures the smooth movement of the HWCR. 相似文献
90.
Silver nanowire (AgNW) based transparent electrodes are inherently coarse and therefore typically are only ever weakly bonded to a substrate. A remarkable improvement in the characteristics of a AgNW network film has, however, been achieved through a simple and short process of irradiating it with intense pulsed light (IPL). This not only avoids any severe deterioration in the optical characteristics of the AgNW film, but also significantly improves its electrical conductivity, adhesion to a polymeric substrate, and ability to endure bending stress. Most important of all, however, is the finding that the surface roughness of AgNW networks can also be improved by radiation. In a series of measurements made of organic light emitting diodes fabricated using these treated electrodes, it was revealed that the leakage current can be notably reduced by IPL treatment. 相似文献