全文获取类型
收费全文 | 5722篇 |
免费 | 483篇 |
国内免费 | 177篇 |
专业分类
电工技术 | 297篇 |
技术理论 | 1篇 |
综合类 | 371篇 |
化学工业 | 1056篇 |
金属工艺 | 402篇 |
机械仪表 | 339篇 |
建筑科学 | 403篇 |
矿业工程 | 216篇 |
能源动力 | 143篇 |
轻工业 | 293篇 |
水利工程 | 97篇 |
石油天然气 | 396篇 |
武器工业 | 37篇 |
无线电 | 574篇 |
一般工业技术 | 759篇 |
冶金工业 | 349篇 |
原子能技术 | 62篇 |
自动化技术 | 587篇 |
出版年
2024年 | 27篇 |
2023年 | 96篇 |
2022年 | 183篇 |
2021年 | 241篇 |
2020年 | 209篇 |
2019年 | 150篇 |
2018年 | 194篇 |
2017年 | 169篇 |
2016年 | 177篇 |
2015年 | 246篇 |
2014年 | 294篇 |
2013年 | 359篇 |
2012年 | 385篇 |
2011年 | 384篇 |
2010年 | 364篇 |
2009年 | 348篇 |
2008年 | 327篇 |
2007年 | 315篇 |
2006年 | 301篇 |
2005年 | 228篇 |
2004年 | 162篇 |
2003年 | 132篇 |
2002年 | 100篇 |
2001年 | 105篇 |
2000年 | 130篇 |
1999年 | 144篇 |
1998年 | 124篇 |
1997年 | 103篇 |
1996年 | 105篇 |
1995年 | 72篇 |
1994年 | 60篇 |
1993年 | 33篇 |
1992年 | 40篇 |
1991年 | 25篇 |
1990年 | 17篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有6382条查询结果,搜索用时 10 毫秒
1.
2.
Zenan Yu Julian Moore Jean Calderon Lei Zhai Jayan Thomas 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(39):5289-5295
Cable‐shaped supercapacitors (SCs) have recently aroused significant attention due to their attractive properties such as small size, lightweight, and bendability. Current cable‐shaped SCs have symmetric device configuration. However, if an asymmetric design is used in cable‐shaped supercapacitors, they would become more attractive due to broader cell operation voltages, which results in higher energy densities. Here, a novel coil‐type asymmetric supercapacitor electrical cable (CASEC) is reported with enhanced cell operation voltage and extraordinary mechanical‐electrochemical stability. The CASECs show excellent charge–discharge profiles, extraordinary rate capability (95.4%), high energy density (0.85 mWh cm−3), remarkable flexibility and bendability, and superior bending cycle stability (≈93.0% after 4000 cycles at different bending states). In addition, the CASECs not only exhibit the capability to store energy but also to transmit electricity simultaneously and independently. The integrated electrical conduction and storage capability of CASECS offer many potential applications in solar energy storage and electronic gadgets. 相似文献
3.
Multibody System Dynamics - This paper represents an explicit analytical solution for attitude dynamics of spacecraft combination during on-orbit refueling. Due to the fuel transfer from the... 相似文献
4.
5.
L. Vu‐Quoc V. Srinivas Y. Zhai 《International journal for numerical methods in engineering》2003,58(3):397-461
We establish a systematic methodology to design and analyse electromagnetic components such as advanced multilayer ceramic capacitors (MLCCs) using the finite element (FE) method. We employ a coupled formulation to compute the interaction between the electric and magnetic fields. Unlike a linear distribution of current assumed in the circuit model, an accurate electrostatic solution to model the entire advanced MLCCs (4 × 4 × 27 = 432 cells) is presented. The FE solution is used to compute the lumped parameters for a range of frequencies. These lumped parameters are then used to compute the parasitic elements of the MLCCs. We introduce two algorithms to efficiently analyse the behaviour of a capacitor with changing frequency. The lower frequency (much below the self‐resonant frequency of the capacitor) algorithm separates the effect of the electric and magnetic fields and reduces the computational effort required to solve the FE problem, whereas, the high‐frequency algorithm couples the effect between the electric and the magnetic fields. We use these algorithms in conjunction with a new multiple scale technique to effectively determine the small values of R, L and C in MLCCs. The formulation, the implementation, and the numerical results demonstrate the efficacy of the present FE formulation and establish a systematic methodology to design and analyse advanced electromagnetic components. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
6.
ImprovingWearResistanceoftheNibaseThermalSprayWeldingCoatingUsingRareEarthsZhaiGuangjie(翟光杰)(InstituteofPhysics,AcademicaSi... 相似文献
7.
8.
9.
10.
随着经济发展、城市化率的提高,加之滨湖开发,骆马湖的水质呈现一定的恶化趋势,生态系统遭受破坏,水体富营养化发展有越来越严重的趋势。通过对骆马湖营养化程度和污染原因的分析,提出了一些对策措施和解决办法,以期实现湖泊的生态、环境与经济的协调发展。 相似文献