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   9498篇
  免费   344篇
  国内免费   40篇
电工技术   124篇
综合类   22篇
化学工业   2183篇
金属工艺   180篇
机械仪表   241篇
建筑科学   601篇
矿业工程   31篇
能源动力   181篇
轻工业   904篇
水利工程   54篇
石油天然气   13篇
武器工业   1篇
无线电   625篇
一般工业技术   1522篇
冶金工业   1611篇
原子能技术   76篇
自动化技术   1513篇
  2023年   51篇
  2022年   102篇
  2021年   148篇
  2020年   106篇
  2019年   126篇
  2018年   174篇
  2017年   114篇
  2016年   200篇
  2015年   198篇
  2014年   253篇
  2013年   609篇
  2012年   415篇
  2011年   561篇
  2010年   426篇
  2009年   412篇
  2008年   449篇
  2007年   440篇
  2006年   380篇
  2005年   329篇
  2004年   303篇
  2003年   231篇
  2002年   237篇
  2001年   181篇
  2000年   174篇
  1999年   161篇
  1998年   286篇
  1997年   208篇
  1996年   172篇
  1995年   151篇
  1994年   136篇
  1993年   147篇
  1992年   130篇
  1991年   83篇
  1990年   97篇
  1989年   82篇
  1988年   101篇
  1987年   70篇
  1986年   62篇
  1985年   90篇
  1984年   102篇
  1983年   65篇
  1982年   73篇
  1981年   95篇
  1980年   73篇
  1979年   88篇
  1978年   78篇
  1977年   77篇
  1976年   65篇
  1975年   60篇
  1973年   47篇
排序方式: 共有9882条查询结果,搜索用时 171 毫秒
91.
CMOS scaling into the nanometer regime   总被引:11,自引:0,他引:11  
Starting with a brief review on 0.1-μm (100 nm) CMOS status, this paper addresses the key challenges in further scaling of CMOS technology into the nanometer (sub-100 nm) regime in light of fundamental physical effects and practical considerations. Among the issues discussed are: lithography, power supply and threshold voltage, short-channel effect, gate oxide, high-field effects, dopant number fluctuations and interconnect delays. The last part of the paper discusses several alternative or unconventional device structures, including silicon-on-insulator (SOI), SiGe MOSFET's, low-temperature CMOS, and double-gate MOSFET's, which may lead to the outermost limits of silicon scaling  相似文献   
92.
The strength and nature of dye–fibre interactions vary according to fibre type and dye type. In the case of acid dyes for polyamide fibres, cationic dyes for acrylic fibres, disperse dyes for hydrophobic fibres, and direct dyes for cellulosic fibres, these interactions may be classified as non-covalent, a classification which includes van der Waals (VDW), electrostatic, induction, solvophobic and charge-transfer interactions.
Reactive dyes are a notable exception to the above, since the interaction which is responsible for their excellent wet fastness is the dye–fibre covalent bond, however, these dyes are increasingly viewed as environmentally unfriendly due to high salt usage and residual unfixed colour. This situation may be improved by either incorporating amine sites in the cellulose or by reversing the system to incorporate reactive residues in the fibre and nucleophilic sites in the dye.
Nonionic disperse dyes are valuable for hydrophobic fibres such as polyester but have made little impact on hydrophilic fibres such as silk, wool and cotton. Experiments to develop simple treatments to render the latter fibres disperse dyeable are described and the combined role of solvophobic and – interactions discussed.  相似文献   
93.
The structure of ultrathin silicon layers obtained by molecular hydrophobic bonding is investigated. The twist and tilt angles between the two crystals are accurately controlled. The buried Si|Si interface is observed by transmission electron microscopy and by grazing incidence X-ray techniques. For low twist angle values (/spl psi/<5/spl deg/) plane view observations reveal well-defined dislocation networks. Cross-section observations give evidence that the dislocation networks are localized at the bonding interfacial plane with no threading dislocation. Grazing incidence small angle X-ray scattering measurements confirm the good quality of the bonding interface as well as the quality of the dislocation networks. Grazing incidence X-ray diffraction is also used and shows the long-range order of the periodic strain field in the silicon layer. It shows, especially, the interaction between the dislocations. X-ray reflectivity was employed and estimated that the interfacial thickness (i.e., thickness of the bonding) lower than 1 nm decreases when the twist angle increases. The nanopatterned surface is then investigated by scanning tunneling microscopy and X-ray methods. To validate these substrates for long-range order self-organization, the growth of Si and Ge quantum dots is finally achieved.  相似文献   
94.
A circuit is described that determines the average of the transit time of light from an event in a scintillation counter to the two ends of that counter. The design offers superior time resolution and a novel gating scheme that significantly reduces circuit dead-time.  相似文献   
95.
In general, the performance of a KE penetrator against most targets increases with velocity regardless of the particular penetrator-target interaction mode. It is possible to show that there exists an optimum velocity which maximizes the performance of an impacting penetrator for a given expenditure of kinetic energy. Simple graphical methods are described that determine the optimum velocity from general performance-velocity plots. These graphical methods may also be applied to experimental data alone. In addition, simple analytic models which describe the velocity dependent penetration/perforation performance of KE penetrators are examined and extended. These models may be used to explicitly assess the influence of parameters such as target strength and density and penetrator mass, strength and density. For some of the models in this analysis, the explicit relations between the optimum striking velocity for a specific kinetic energy value and the penetrator-target parameters are described.  相似文献   
96.
Much of what has been written in Australia about the protection of computer programs has been inspired by high profile cases concerning the boundaries of copyright protection. The Australian law firm Clayton Utz says that there has been little discussion about other types of legal protection for computer programs, and as a consequence, other intellectual property laws should not be overlooked.  相似文献   
97.
Background, prime influences upon present day methods and current trends in United Kingdom tendering practices are reviewed. Significant weaknesses are identified, confirming the need for some revision of existing contractor selection methods. The findings compliment recommendations of the recent government/industry review of the construction sector headed by Sir Michael Latham. Specifically, that tendering procedure should embrace investigation of contractors' potential to deliver a service of acceptable standard, on time, within budget. Present selection methods often fail in this objective, being inclined to discriminate predominantly on cost.  相似文献   
98.
99.
A robustness analysis and synthesis for incomplete nonlinear decoupling for a class of nonlinear systems is discussed. Rigid and elastic-joint robot models belong to this class. For the elastic case, a transformation facilitates the robustness analysis under a weak assumption. Charts with H 1- and H - norms of closed-loop disturbance transfer functions of the nonlinear-decoupled system are presented for a robust pole assignment.  相似文献   
100.
Neural Computing and Applications - In the medical imaging domain, nonlinear warping has enabled pixel-by-pixel mapping of one image dataset to a reference dataset. This co-registration of data...  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