全文获取类型
收费全文 | 21322篇 |
免费 | 2334篇 |
国内免费 | 1035篇 |
专业分类
电工技术 | 1316篇 |
技术理论 | 1篇 |
综合类 | 2224篇 |
化学工业 | 601篇 |
金属工艺 | 307篇 |
机械仪表 | 1217篇 |
建筑科学 | 11365篇 |
矿业工程 | 1166篇 |
能源动力 | 231篇 |
轻工业 | 326篇 |
水利工程 | 1004篇 |
石油天然气 | 317篇 |
武器工业 | 90篇 |
无线电 | 1069篇 |
一般工业技术 | 1904篇 |
冶金工业 | 232篇 |
原子能技术 | 25篇 |
自动化技术 | 1296篇 |
出版年
2024年 | 111篇 |
2023年 | 353篇 |
2022年 | 466篇 |
2021年 | 631篇 |
2020年 | 631篇 |
2019年 | 549篇 |
2018年 | 569篇 |
2017年 | 592篇 |
2016年 | 632篇 |
2015年 | 730篇 |
2014年 | 1523篇 |
2013年 | 936篇 |
2012年 | 1487篇 |
2011年 | 1520篇 |
2010年 | 1460篇 |
2009年 | 1573篇 |
2008年 | 1406篇 |
2007年 | 1729篇 |
2006年 | 1461篇 |
2005年 | 1240篇 |
2004年 | 973篇 |
2003年 | 822篇 |
2002年 | 672篇 |
2001年 | 585篇 |
2000年 | 477篇 |
1999年 | 375篇 |
1998年 | 298篇 |
1997年 | 245篇 |
1996年 | 182篇 |
1995年 | 134篇 |
1994年 | 102篇 |
1993年 | 49篇 |
1992年 | 60篇 |
1991年 | 32篇 |
1990年 | 18篇 |
1989年 | 23篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 14篇 |
1977年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films are attracting famous applications in antistatic coating, energy storage and conversion, printed electronics, and biomedical fields due to their conductivity, optical transparency and flexibility. However, PEDOT:PSS has poor dispersion stability during long-term storage and transport. Moreover, the dried PEDOT:PSS films are insoluble in any solvent and cannot be redispersed again. In comparison to bake drying, here, a feasible strategy to achieve mechanically redispersed PEDOT:PSS with the help of freeze-drying process was reported. The redispersed PEDOT:PSS can recover not only the initial characters such as pH, chemical composition, viscosity, and particle size under similar solid contents, but also conductivity and surface morphology of treated films. In addition, the treated film exhibits self-healing properties similar to pristine film in terms of mechanical and electrical properties. This technology enables reuse and overcomes the technical problems of PEDOT:PSS dispersion, realizing real-time processing to meet variable applications. 相似文献
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.
Adaptive robust boundary control of shaft vibrations under perturbations with unknown upper bounds
下载免费PDF全文
![点击此处可从《International Journal of Adaptive Control and Signal Processing》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This paper presents robust and adaptive boundary control designs to stabilize the two‐dimensional vibration of hybrid shaft model. The hybrid shaft is mathematically represented by a set of partial differential equations, governing the shaft vibrations, coupled to ordinary differential equations, describing rigid body spinning and dynamic boundary conditions. The control objective is to stabilize the transverse vibrations of the perturbed shaft while regulating the spinning rate. To achieve this, the paper first establishes robust boundary control laws that fulfil the control objective in the presence of modeling uncertainties and external disturbances operating over the shaft domain and boundary. Lyapunov‐based analyses show that the proposed robust control exponentially stabilizes the shaft with vanishing distributive perturbations, while assuring ultimately bounded vibrations in the case of nonvanishing perturbations. Then, adaptive control philosophy is utilized to achieve redesigned robust controllers that only use online adaptation of control gains without acquiring the knowledge of bounds on perturbations, as well as dynamic parameters. An advantage of this design is avoiding an overconservative robust control law, which may induce poor stability and chattering in tackling system perturbations with unknown upper bounds. Simulations through finite element method illustrate the results. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
4.
5.
双排桩门架—锚杆新型组合支护体系的应用研究 总被引:1,自引:0,他引:1
本文分析了双排桩门架支护结构的受力机理。针对工程实际进行变形分析,提出增设锚杆形成锚杆———双排桩门架式组合支护体系的方法,并与监测数据对比、验证。 相似文献
6.
7.
8.
9.
谐波齿轮机构在商业表格印刷机中的应用 总被引:1,自引:1,他引:0
从商业表格印刷机特殊要求出发,以某一具体机型的传动系统为例,提出采用谐波齿轮机构解决纵向套准的问题。并且分析研究了谐波齿轮机构的工作原理及其在商业表格印刷机中的使用。 相似文献
10.
粉喷桩处理软弱地基在祁临高速公路的应用 总被引:1,自引:1,他引:0
结合工程实例,介绍了粉喷桩的所属类型,粉喷桩对软弱地基加固的原因,所适应土质及加固特点,阐述了祁临十八合同段的粉喷桩施工过程及施工中应注意的若干问题,得出粉喷桩处理不良地基效果良好。 相似文献