首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9591篇
  免费   1137篇
  国内免费   572篇
电工技术   813篇
技术理论   1篇
综合类   738篇
化学工业   1583篇
金属工艺   644篇
机械仪表   505篇
建筑科学   874篇
矿业工程   352篇
能源动力   237篇
轻工业   811篇
水利工程   227篇
石油天然气   513篇
武器工业   65篇
无线电   1024篇
一般工业技术   1057篇
冶金工业   394篇
原子能技术   167篇
自动化技术   1295篇
  2024年   51篇
  2023年   164篇
  2022年   410篇
  2021年   480篇
  2020年   397篇
  2019年   309篇
  2018年   289篇
  2017年   313篇
  2016年   268篇
  2015年   463篇
  2014年   527篇
  2013年   537篇
  2012年   596篇
  2011年   573篇
  2010年   559篇
  2009年   520篇
  2008年   527篇
  2007年   476篇
  2006年   447篇
  2005年   357篇
  2004年   370篇
  2003年   446篇
  2002年   618篇
  2001年   520篇
  2000年   253篇
  1999年   224篇
  1998年   125篇
  1997年   82篇
  1996年   67篇
  1995年   71篇
  1994年   47篇
  1993年   59篇
  1992年   38篇
  1991年   31篇
  1990年   24篇
  1989年   18篇
  1988年   7篇
  1987年   13篇
  1986年   3篇
  1985年   7篇
  1984年   1篇
  1983年   2篇
  1982年   3篇
  1981年   1篇
  1980年   2篇
  1978年   1篇
  1959年   1篇
  1951年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
A novel series of temperature‐sensitive poly[(N‐isopropylacrylamide)‐co‐(ethyl methacrylate)] (p(NIPAM‐co‐EMA)) microgels was prepared by the surfactant‐free radical polymerization of N‐isopropylacrylamide (NIPAM) with ethyl methacrylate (EMA). The shape, size dispersity and volume‐phase transition behavior of the microgels were investigated by transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy, dynamic light scattering (DLS) and differential scanning calorimetry (DSC). The transmission electron micrographs and DLS results showed that microgels with narrow distributions were prepared. It was shown from UV–Vis, DLS and DSC measurements that the volume‐phase transition temperature (VPTT) of the p(NIPAM‐co‐EMA) microgels decreased with increasing incorporation of EMA, but the temperature‐sensitivity was impaired when more EMA was incorporated, causing the volume‐phase transition of the microgels to become more continuous. It is noteworthy that incorporation of moderate amounts of EMA could not only lower the VPTT but also enhance the temperature‐sensitivity of the microgels. The reason for this phenomenon could be attributed to changes in the complicated interactions between the various molecules. Copyright © 2004 Society of Chemical Industry  相似文献   
2.
直接斜率波前复原算法的控制效果分析   总被引:7,自引:0,他引:7  
建立自适应光学系统功率谱抑制函数的概念,分析了采用直接斜率波前复原算法的自适应当光学系统的控制效果,理论分析与61单元自适应光学系统上的实验结果表明,直接斜率波前复原算法将导致控制效果下降。  相似文献   
3.
ABSTRACT

In this research, the effect of particle size on the surface oxidation and flotation behavior of galena in the lime system was studied. Coarse (?0.074 + 0.038 mm), intermediate (?0.038 + 0.025 mm) and fine (?0.025 mm) galena particles were used in the experiment. The dissolution tests, flotation tests, and sorption tests were accomplished. Through further analysis by XPS, the effect of particle size and lime was observed. The decrease of mineral particle sizes increased the adsorption ratio of collector and the dissolution of galena, while the hydrophilic product OH?/Ca(OH)+ produced by dissolution occupied the dominant position, which led to the minerals hydrophilic.  相似文献   
4.
Following logic in the silicon semiconductor industry, the existence of native oxide and suitable fabrication technology is essential for 2D semiconductors in planar integronics, which are surface-sensitive to typical coating technologies. To date, very few types of integronics are found to possess this feature. Herein, the 2D Bi2O2Te developed recently is reported to possess large-area synthesis and controllable thermal oxidation behavior toward single-crystal native oxides. This shows that surface-adsorbed oxygen atoms are inclined to penetrate across [Bi2O2]n2n+ layers and bond with the underlying [Te]n2n− at elevated temperatures, transforming directly into [TeO4]n2n− with the basic architecture remaining stable. The oxide can be adjusted to form in an accurate layer-by-layer manner with a low-stress sharp interface. The native oxide Bi2TeO6 layer (bandgap of ≈2.9 eV) exhibits visible-light transparency and is compatible with wet-chemical selective etching technology. These advances demonstrate the potential of Bi2O2Te in planar-integrated functional nanoelectronics such as tunnel junction devices, field-effect transistors, and memristors.  相似文献   
5.
In electronic systems, dynamic random access memory (DRAM) is one of the core modules in the modern silicon computer. As for a bio‐computer, one would need a mechanism for storage of bio‐information named ‘data’, which, in binary logic, has two levels, logical high and logical low, or in the normalised form, ‘1’ and ‘0’. This study proposes a possible genetic DRAM based on the modified electronic configuration, which uses the biological reaction to fulfil an equivalent RC circuit constituting a memory cell. The authors implement fundamental functions of the genetic DRAM by incorporating a genetic toggle switch for data hold. The results of simulation verify that the basic function can be used on a bio‐storage module for the future bio‐computer.Inspec keywords: DRAM chips, genetic engineering, biocomputers, bioinformatics, equivalent circuits, RC circuitsOther keywords: dynamic genetic memory design, electronic systems, dynamic random access memory, modern silicon computer, biocomputer, bioinformation, binary logic, logical high level, logical low level, normalised form, genetic DRAM, modified electronic configuration, biological reaction, equivalent RC circuit, memory cell, fundamental functions, genetic toggle switch, data hold, biostorage module  相似文献   
6.
Ren  Wuyang  Li  Handong  Gao  Lei  Li  Yong  Zhang  Zhongyang  Long  Chengjia  Ji  Haining  Niu  Xiaobin  Lin  Yuan  Wang  Zhiming 《Nano Research》2017,10(1):247-254
Nano Research - Thermal transport in superlattices is governed by various phonon-scattering processes. For extracting the phonon-scattering contribution of hetero-interfaces in chalcogenide...  相似文献   
7.
An experiment on fitness of one-piece casting osseointegrated implant frameworks was performed among three fixture abument positions where other conditions were controlled. The result revealed that there was statistically significant differences in dimensional change among the three fixture abument positions. In terms of the relation between abument position and fitness, the more backward the abument position was, the worse the osseointegrated framework fitness was. The frameworks showed deformations in "arch form" and "warp" in three dimensions.  相似文献   
8.
杨华  马先  刘媛 《控制工程》2001,8(1):56-58
对于特种异步电动机拖动的高压阀门 ,切断电动机交流供电电源后 ,在电机的定子绕组中通入适当的直流电流 ,产生直流磁场 ,使电机进行能耗制动 ,让阀心和电机转子的能量 ,包括动能消耗在转子的绕组中 ,达到准确停车的目的。介绍了这一过程的计算机仿真计算  相似文献   
9.
请求式拨号网络还存在着冗余很大的网络传输和拨号连接,为减少电信成本,文章尝试对Windows NT请求式拨号网络进行优化。  相似文献   
10.
水性木器装修清漆的研制   总被引:1,自引:2,他引:1  
以水性聚氨酯分散体与丙烯酸乳液及其混合液为成膜物 ,选用几种合适的助剂 ,研制出性能价格比良好的水性木器装修清漆。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号