全文获取类型
收费全文 | 2818篇 |
免费 | 118篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 32篇 |
化学工业 | 527篇 |
金属工艺 | 39篇 |
机械仪表 | 66篇 |
建筑科学 | 159篇 |
矿业工程 | 11篇 |
能源动力 | 150篇 |
轻工业 | 241篇 |
水利工程 | 24篇 |
石油天然气 | 2篇 |
无线电 | 247篇 |
一般工业技术 | 581篇 |
冶金工业 | 185篇 |
原子能技术 | 15篇 |
自动化技术 | 660篇 |
出版年
2024年 | 5篇 |
2023年 | 21篇 |
2022年 | 47篇 |
2021年 | 65篇 |
2020年 | 51篇 |
2019年 | 61篇 |
2018年 | 63篇 |
2017年 | 76篇 |
2016年 | 97篇 |
2015年 | 72篇 |
2014年 | 111篇 |
2013年 | 196篇 |
2012年 | 197篇 |
2011年 | 249篇 |
2010年 | 160篇 |
2009年 | 154篇 |
2008年 | 176篇 |
2007年 | 151篇 |
2006年 | 123篇 |
2005年 | 110篇 |
2004年 | 94篇 |
2003年 | 81篇 |
2002年 | 73篇 |
2001年 | 55篇 |
2000年 | 39篇 |
1999年 | 34篇 |
1998年 | 36篇 |
1997年 | 33篇 |
1996年 | 21篇 |
1995年 | 29篇 |
1994年 | 20篇 |
1993年 | 8篇 |
1992年 | 15篇 |
1991年 | 16篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 12篇 |
1985年 | 14篇 |
1984年 | 16篇 |
1983年 | 14篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 11篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 11篇 |
1973年 | 6篇 |
排序方式: 共有2939条查询结果,搜索用时 15 毫秒
31.
Media‐based fact checking contributes to more accurate political knowledge, but its corrective effects are limited. We argue that biographical information included in a corrective message, which is often unrelated to the inaccurate claim itself, can activate misperception‐congruent naïve theories, increasing confidence in a misperception's plausibility and inducing skepticism toward denials. Resistance to corrections occurs regardless of initial belief accuracy, but the effect is strongest among those who find the contextual information objectionable or threatening. We test these claims using an online survey‐embedded experiment (N = 750) conducted in the wake of the controversy over the proposed Islamic cultural center in New York City near the site of the 9/11 attacks, and find support for our predictions. Theoretical and practical implications are discussed. 相似文献
32.
Gunnar Gudnason Erik Bruun Morten Haugland 《Analog Integrated Circuits and Signal Processing》2000,22(1):81-89
This paper describes a chip for a multichannel neural stimulator for functional electrical stimulation (FES). The purpose of FES is to restore muscular control in disabled patients. The chip performs all the signal processing required in an implanted neural stimulator. The power and digital data transmission to the stimulator passes through a 5 MHz inductive link. From the signals transmitted to the stimulator, the chip is able to generate charge-balanced current pulses with a controllable length up to 256 s and an amplitude up to 2 mA, for stimulation of nerve fibers. The quiescent current consumption of the chip is approx. 650 A at supply voltages of 6–12 V, and its size is 3.9×3.5 mm2. It has 4 output channels for use in a multipolar cuff electrode. 相似文献
33.
ErnoLangendijk MichielKlompenhouwer ErikvanderTol 《现代显示》2005,(4):25-29
新的视频处理算法显著地改善了典型的可移动显示器的图像质量,而不管它们有限的颜色再现性。 相似文献
34.
It is possible in many cases by using space-time integral equations to compute the scattering and penetration of electromagnetic fields via explicit time-stepping diagrams. The case of conducting surfaces, thin scatterers, apertures and shieldings of finite conductivity are discussed with emphasis on the simplicity and the validity domain of the relevant equations. Examples concern the field of a far-located dipole incident on a cylinder with infinite conductivity, with an aperture or with resistive walls. 相似文献
35.
Erik R. Fledderus 《Wireless Personal Communications》2005,33(3-4):319-325
The paper describes three relevant perspectives on current wireless simulation practices. In order to obtain the key challenges for future network simulations, the characteristics of “beyond 3G” networks are described, including their impact on simulation.Erik Fledderus (1970) received a PhD in Applied Mathematics in 1997, after which he started working at KPN Research, which merged with TNO in January 2003. He developed the basis for UMTS radio network planning at KPN, and initiated in 2000 a European project proposal, Momentum, in the area of UMTS radio planning and simulation, with 7 partners from Germany and Pottugal. Erik acted as project leader and co-ordinator from 2001-2003. Also at the end of 2000 he initiated together with Eindhoven University of Technology, Agere Systems and Philips Research a research proposal in the area of antenna arrays and MIMO in WLAN and UMTS. One of the results of this project~lies at the basis for the 802.11n-proposal by Agere/Philips.Since March 1st 2003, Erik is part-time professor at Eindhoven University of Technology in the field of Wireless Communication Networks.Within TNO he is senior strategist, program manager of the program Future ICT Architectures, and leading in the knowledge management regarding radio and mobile network technology, and strategist on mobile/wireless technology in general. 相似文献
36.
Michael Sillassen Per Eklund Nini Pryds Erik Johnson Ulf Helmersson Jørgen Bøttiger 《Advanced functional materials》2010,20(13):2071-2076
Very high lateral ionic conductivities in epitaxial cubic yttria‐stabilized zirconia (YSZ) synthesized on single‐crystal SrTiO3 and MgO substrates by reactive direct current magnetron sputtering are reported. Superionic conductivities (i.e., ionic conductivities of the order ~1 Ω?1cm?1) are observed at 500 °C for 58‐nm‐thick films on MgO. The results indicate a superposition of two parallel contributions – one due to bulk conductivity and one attributable to conduction along the film–substrate interface. Interfacial effects dominate the conductivity at low temperatures (<350 °C), showing more than three orders of magnitude enhancement compared to bulk YSZ. At higher temperatures, a more bulk‐like conductivity is observed. The films have a negligible grain‐boundary network, thus ruling out grain boundaries as a pathway for ionic conduction. The observed enhancement in lateral ionic conductivity is caused by a combination of misfit dislocation density and elastic strain in the interface. These very high ionic conductivities in the temperature range 150–500 °C are of great fundamental importance but may also be technologically relevant for low‐temperature applications. 相似文献
37.
Kaplan AD O'Sullivan JA Sirevaag EJ Lai PH Rohrbaugh JW 《IEEE transactions on bio-medical engineering》2012,59(3):744-753
The method of laser Doppler vibrometry (LDV) is used to sense movements of the skin overlying the carotid artery. When pointed at the skin overlying the carotid artery, the mechanical movements of the skin disclose physiological activity relating to the blood pressure pulse over the cardiac cycle. In this paper, signal modeling is addressed, with close attention to the underlying physiology. Segments of the LDV signal corresponding to single heartbeats, called LDV pulses, are extracted. Hidden Markov models (HMMs) are used to capture the dynamics of the LDV pulses from beat to beat based on pulse morphology; under resting conditions these dynamics are primarily due to respiration-related effects. LDV pulses are classified according to state, by computing the optimal state path through the data using trained HMMs. HMM state dynamics are examined within the context of respiratory effort using strain gauges placed around the abdomen. This study presented here provides a graphical model approach to modeling the dependence of the LDV pulse on latent states. 相似文献
38.
Traditional acoustic speech recognition accuracies have been shown to deteriorate in highly noisy environments. A secondary information source is exploited using surface myoelectric signals (MES) collected from facial articulatory muscles during speech. Words are classified at the phoneme level using a hidden Markov model (HMM) classifier. Acoustic and MES data was collected while the words "zero" through "nine" were spoken. An acoustic expert classified the 18 formative phonemes in low noise levels [signal-to-noise ratio (SNR) of 17.5 dB] with an accuracy of 99%, but deteriorated to approximately 38% under simulations with SNR approaching 0 dB. A fused acoustic-myoelectric multiexpert system, without knowledge of SNR, improved on acoustic classification results at all noise levels. A multiexpert system, incorporating SNR information, obtained accuracies of 99% at low noise levels while maintaining accuracies above 94% during low SNR (0 dB) simulations. Results improve on previous full word MES speech recognition accuracies by almost 10%. 相似文献
39.
Erik Benkler Andreas G. Steffan Harald R. Telle 《Photonics Technology Letters, IEEE》2007,19(5):267-269
We demonstrate a novel synchronization scheme for optical sampling which is based on a nonstandard phase-locked loop (PLL). Phase comparison is performed at a 10-GHz optical time-division-multiplexing (OTDM) base rate, thus avoiding ultrafast detectors and electronics. The employed frequency-offset PLL allows synchronous sampling of OTDM signals (or any other signals with bit rates given by integer multiples of the base rate), which would be impossible using a standard PLL. This provides a higher degree of flexibility for problem-specific sweeping than asynchronous sampling 相似文献
40.
Olof Eskilson Stefan B. Lindstrm Borja Sepulveda Mohammad M. Shahjamali Pau Güell‐Grau Petter Sivlr Mrten Skog Christopher Aronsson Emma M. Bjrk Niklas Nyberg Hazem Khalaf Torbjrn Bengtsson Jeemol James Marica B. Ericson Erik Martinsson Robert Selegrd Daniel Aili 《Advanced functional materials》2020,30(40)
Nanocomposites of metal nanoparticles (NPs) and bacterial nanocellulose (BC) enable fabrication of soft and biocompatible materials for optical, catalytic, electronic, and biomedical applications. Current BC–NP nanocomposites are typically prepared by in situ synthesis of the NPs or electrostatic adsorption of surface functionalized NPs, which limits possibilities to control and tune NP size, shape, concentration, and surface chemistry and influences the properties and performance of the materials. Here a self‐assembly strategy is described for fabrication of complex and well‐defined BC–NP composites using colloidal gold and silver NPs of different sizes, shapes, and concentrations. The self‐assembly process results in nanocomposites with distinct biophysical and optical properties. In addition to antibacterial materials and materials with excellent senor performance, materials with unique mechanoplasmonic properties are developed. The homogenous incorporation of plasmonic gold NPs in the BC enables extensive modulation of the optical properties by mechanical stimuli. Compression gives rise to near‐field coupling between adsorbed NPs, resulting in tunable spectral variations and enhanced broadband absorption that amplify both nonlinear optical and thermoplasmonic effects and enables novel biosensing strategies. 相似文献