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   3068篇
  免费   64篇
  国内免费   11篇
电工技术   50篇
综合类   2篇
化学工业   453篇
金属工艺   91篇
机械仪表   174篇
建筑科学   58篇
矿业工程   3篇
能源动力   113篇
轻工业   121篇
水利工程   30篇
石油天然气   9篇
无线电   540篇
一般工业技术   540篇
冶金工业   379篇
原子能技术   18篇
自动化技术   562篇
  2023年   31篇
  2022年   67篇
  2021年   71篇
  2020年   61篇
  2019年   67篇
  2018年   89篇
  2017年   70篇
  2016年   91篇
  2015年   67篇
  2014年   78篇
  2013年   188篇
  2012年   105篇
  2011年   141篇
  2010年   115篇
  2009年   116篇
  2008年   108篇
  2007年   111篇
  2006年   97篇
  2005年   80篇
  2004年   62篇
  2003年   59篇
  2002年   69篇
  2001年   56篇
  2000年   65篇
  1999年   62篇
  1998年   122篇
  1997年   84篇
  1996年   86篇
  1995年   52篇
  1994年   51篇
  1993年   45篇
  1992年   47篇
  1991年   35篇
  1990年   40篇
  1989年   39篇
  1988年   32篇
  1987年   30篇
  1986年   27篇
  1985年   35篇
  1984年   22篇
  1983年   32篇
  1982年   28篇
  1981年   30篇
  1980年   29篇
  1979年   34篇
  1978年   18篇
  1977年   18篇
  1976年   23篇
  1975年   11篇
  1973年   11篇
排序方式: 共有3143条查询结果,搜索用时 10 毫秒
991.
A two dimensional analytical model for nanoscale fully depleted double gate SOI MOSFET is presented. Green??s function solution technique is adopted to solve the two dimensional Poisson??s equation using Dirichlet??s and Neumann??s boundary conditions at silicon-silicon di-oxide interface. Based on the derived 2D potential distribution, surface potential distributions in the Si film are analytically obtained. The calculated minimum surface potential is used to develop an analytic threshold voltage model. Simulation is done using ATLAS simulator for a 65?nm device and the results obtained are compared with the proposed 2D model. The model results are found to be in good agreement with the simulated data and other published results.  相似文献   
992.
Kansal  Harshit  Medury  Aditya Sankar 《SILICON》2023,15(4):1961-1966
Silicon - In this paper, through TCAD simulations, we show that the introduction of a thin paraelectric (PE) layer between the ferroelectric (FE) and dielectric (DE) layers in an MFIS structure,...  相似文献   
993.
The scarcity of freshwater is one of the major challenges to the civilized community around the World. So, the various engineered processes have been developed for the remediation of this problem such as osmotic pressure-driven processes (OPDPs). OPDPs includes forward osmosis and pressure retarded osmosis, which have gained enormous attention and becoming a flexible membrane-based technology for desalination and wastewater treatment. The most significant components of the OPDPs to be efficient are the membranes and the draw solution. Although numerous studies highlighted the membrane fouling and concentration polarization are one of the critical parameters to assess the system efficiency in the OPDPs and other pressure driven membrane processes. This study delivers an up-to-date review of the OPDPs in terms of concentration polarization, membrane fouling (organic, inorganic, and biofouling), foulant interactions, remedial strategies, monitoring and characterization techniques, and future directions of research. Numerous foulant interactions are also elaborated for the OPDPs in the field of the membrane separation technique. State of the art in antifouling membrane fabrication methods are critically reviewed along with different remedial strategies for fouled membranes in OPDPs.  相似文献   
994.
This article reports the synthesis and characterisation of Barium titanate (BaTiO3) nanocomposite and its application as opto-electronic humidity sensor. Titanium tetrachloride and barium hydroxide were mixed in molar ratio 1?:?1 in deionised water under continuous stirring at room temperature. Later, sodium hydroxide solution was added to above solution with continuous stirring. Finally, BaTiO3 gel was obtained. The synthesised nano-composite material was characterised using a scanning electron microscope, X-ray diffraction (XRD) and UV-Visible spectrophotometer. SEM image of the composite film shows that the film is porous having uniform grains. From XRD the minimum crystallite size of BaTiO3 was found to be 8?nm using Debye–Scherer formula. UV-Visible absorption spectroscopy was used for optical characterisation of the film. It was found that the optical band gap of the composite material was 3.50?eV. Barium titanate thin film was deposited on the base of an equilateral prism using sol–gel spin coating process at 4000?rpm. The humidity sensing properties of the film was investigated at different angles of incidence. It was observed that the intensity of reflected light increased with an increase in relative humidity (%RH) in the range 5–95% at a particular angle of incidence. Sensing element has maximum sensitivity ~6?µW/%RH, which is quite significant for sensor fabrication purposes.  相似文献   
995.
The monodispersion of magnetic nanoparticles in conducting polymer is the prerequisite to make a high quality composite for tunable electromagnetic interference (EMI) shielding. To meet this challenge, we have designed and synthesized ferrofluid based nanoarchitectured polypyrrole composites containing Fe3O4 (8–12 nm) via in situ oxidative polymerization. To tune the microwave signals, polypyrrole composites (PFF) with different monomer/ferrofluid weight ratios have been prepared and characterized in microwave frequency domain. A maximum shielding effectiveness value of SEA(max) = 20.4 dB (∼99% attenuation) due to the absorption of microwave has been observed in the frequency range of 12.4–18 GHz and attenuation level varied with ferrofluid loading. The electrical conductivity of PFF composite is of the order of 10−2 S cm−1 order and having superparamagnetic nature with saturation magnetization (Ms) of 5.5 emu g−1. The lightweight PFF composites with high attenuations can provide full control over the atomic structure and are favorable for the practical EMI shielding application for commercial electronic appliances.  相似文献   
996.
In this work, Copper Indium disulfide (CIS) nanoparticles of size ∼ 5 nm were prepared via solvothermal approach in ethanol under the nitrogen atmosphere using copper chloride, indium chloride and thiourea (Tu) as starting materials, without any assistance through organic ligands at the reaction temperature of 150 °C. The factors which might affect the morphology, structure, phase of the product during the synthesis were discussed. It was found that the products were significantly affected by the reaction time and solvent. The morphology, structure, phase constituents and optical properties of the as prepared CIS powders were characterized by X-ray diffraction (XRD), Energy dispersive Spectroscopy (EDS), scanning electron microscopy (SEM) and ultraviolet–visible (UV–Vis) spectrometry respectively. The result shows that the CIS nanoparticles can be synthesized by solvothermal method at a reaction time of 2 h and shows that when the reaction time was increased from 2 h to 48 h, CIS porous flower like nanoparticles were obtained as we increase the reaction time. We also observed that in this process, the phase selection of WZ-CIS or CH-CIS is greatly influence by solvent. We also observed that, in this process sulfur source did not influence the phase but participated in the growth of the nanoparticles.  相似文献   
997.
998.
Reactive dissolution and its effects on electrical conduction, morphological change and chemical transformation in thin films of Mg, AZ31B Mg alloy, Zn, Fe, W, and Mo in de‐ionized (DI) water and simulated body fluids (Hanks’ solution pH 5–8) are systematically studied, to assess the potential for use of these metals in water‐soluble, that is, physically "transient", electronics. The results indicate that the electrical dissolution rates in thin films can be much different that traditionally reported corrosion rates in corresponding bulk materials. Silicon metal oxide field effect transistors (MOSFETs) built with these metals demonstrate feasibility for use in transient electronics.  相似文献   
999.
This paper presents an efficient image denoising method that adaptively combines the features of wavelets, wave atoms and curvelets. Wavelet shrinkage is used to denoise the smooth regions in the image while wave atoms are employed to denoise the textures, and the edges will take advantage of curvelet denoising. The received noisy image is firstly decomposed into a homogenous (smooth/cartoon) part and a textural part. The cartoon part of the noisy image is denoised using wavelet transform, and the texture part of the noisy image is denoised using wave atoms. The two denoised images are then fused adaptively. For adaptive fusion, different weights are chosen from the variance map of the denoised texture image. Further improvement in denoising results is achieved by denoising the edges through curvelet transform. The information about edge location is gathered from the variance map of denoised cartoon image. The denoised image results in perfect presentation of the smooth regions and efficient preservation of textures and edges in the image.  相似文献   
1000.
Emerging hybrid reconfigurable platforms tightly couple capable processors with high performance reconfigurable fabrics. This promises to move the focus of reconfigurable computing systems from static accelerators to a more software oriented view, where reconfiguration is a key enabler for exploiting the available resources. This requires a revised look at how to manage the execution of such hardware tasks within a processor-based system, and in doing so, how to virtualize the resources to ensure isolation and predictability. This view is further supported by trends towards amalgamation of computation in the automotive and avionics domains, where such properties are essential to overall system reliability. We present the virtualized execution and management of software and hardware tasks using a microkernel-based hypervisor running on a commercial hybrid computing platform (the Xilinx Zynq). The CODEZERO hypervisor has been modified to leverage the capabilities of the FPGA fabric, with support for discrete hardware accelerators, dynamically reconfigurable regions, and regions of virtual fabric. We characterise the communication overheads in such a hybrid system to motivate the importance of lean management, before quantifying the context switch overhead of the hypervisor approach. We then compare the resulting idle time for a standard Linux implementation and the proposed hypervisor method, showing two orders of magnitude improved performance with the hypervisor.  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