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   387篇
  免费   16篇
电工技术   1篇
化学工业   116篇
金属工艺   5篇
机械仪表   4篇
建筑科学   15篇
能源动力   25篇
轻工业   24篇
水利工程   1篇
石油天然气   1篇
无线电   34篇
一般工业技术   60篇
冶金工业   24篇
原子能技术   1篇
自动化技术   92篇
  2023年   2篇
  2022年   12篇
  2021年   15篇
  2020年   12篇
  2019年   7篇
  2018年   11篇
  2017年   8篇
  2016年   16篇
  2015年   12篇
  2014年   18篇
  2013年   34篇
  2012年   15篇
  2011年   28篇
  2010年   19篇
  2009年   16篇
  2008年   25篇
  2007年   15篇
  2006年   14篇
  2005年   8篇
  2004年   13篇
  2003年   4篇
  2002年   15篇
  2001年   9篇
  2000年   11篇
  1999年   5篇
  1998年   14篇
  1997年   4篇
  1996年   3篇
  1995年   1篇
  1994年   2篇
  1993年   4篇
  1992年   3篇
  1990年   1篇
  1989年   4篇
  1988年   2篇
  1987年   4篇
  1986年   3篇
  1985年   1篇
  1984年   2篇
  1983年   1篇
  1981年   1篇
  1979年   3篇
  1978年   1篇
  1977年   2篇
  1973年   1篇
  1966年   2篇
排序方式: 共有403条查询结果,搜索用时 15 毫秒
101.
Pattern Analysis and Applications - A correction to this paper has been published: 10.1007/s10044-021-01012-9  相似文献   
102.
As synchrotron radiation becomes more intense, detectors become faster and structure‐solving software becomes more elaborate, obtaining single crystals suitable for data collection is now the bottleneck in macromolecular crystallography. Hence, there is a need for novel and advanced crystallisation agents with the ability to crystallise proteins that are otherwise challenging. Here, an Anderson–Evans‐type polyoxometalate (POM), specifically Na6[TeW6O24] ? 22 H2O (TEW), is employed as a crystallisation additive. Its effects on protein crystallisation are demonstrated with hen egg‐white lysozyme (HEWL), which co‐crystallises with TEW in the vicinity (or within) the liquid–liquid phase separation (LLPS) region. The X‐ray structure (PDB ID: 4PHI) determination revealed that TEW molecules are part of the crystal lattice, thus demonstrating specific binding to HEWL with electrostatic interactions and hydrogen bonds. The negatively charged TEW polyoxotungstate binds to sites with a positive electrostatic potential located between two (or more) symmetry‐related protein chains. Thus, TEW facilitates the formation of protein–protein interfaces of otherwise repulsive surfaces, and thereby the realisation of a stable crystal lattice. In addition to retaining the isomorphicity of the protein structure, the anomalous scattering of the POMs was used for macromolecular phasing. The results suggest that hexatungstotellurate(VI) has great potential as a crystallisation additive to promote both protein crystallisation and structure elucidation.  相似文献   
103.
This article presents a new clean power technique for wind energy system based on Unified Power Quality Conditioner (UPQC) with usage of various Artificial Intelligent techniques (AI). Application of AI techniques such as Artificial Neural Networks, Fuzzy Logic is growing fast in the area of power electronics equipment‐based wind energy system, for instance, UPQC. A novel control scheme is developed by using different AI techniques to mitigate the balancing issues and to control the power–quality problems in UPQC and hence to provide clean power to the grid. The proposed system is composed of shunt active power filter, and the inherent proportional integral (PI) control parameters are tuned with application of PI techniques. A detailed Matlab simulation study is carried out with an application of PI techniques under sag, swell, unbalanced, and harmonic conditions. An exhaustive simulation study is carried out to investigate the application of PI technique‐based controllers and compare its performance with the conventional PI controller with its results explored. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
104.
Investigations of memory impairment in schizophrenia have frequently revealed a strategic processing deficit at encoding. The authors studied an early encoding process, refreshing (in this case, thinking of a stimulus that has just-previously been presented), and its impact on recognition memory in schizophrenia. Following simultaneous presentation of three words or a single word in the top, middle, or bottom position of the screen, 25 patients with schizophrenia and 25 control participants saw and read a new word (read condition), or a word presented on the previous screen (repeat condition), or saw a dot indicating that they should think of and say the last word to have appeared in that position (refresh condition). Later, on a surprise test, participants were asked to recognize words seen previously and give a Remember, Know, or Guess response according to whether they recognized each on the basis of conscious recollection, familiarity, or guessing. The cognitive operation of refreshing was impaired in schizophrenia: patients were slower on 1-word trials and less accurate on 3-word trials to refresh a word, and their Remember responses did not benefit from refreshing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
105.
The appearance of a static scene as sensed by a camera changes considerably as a result of changes in the illumination that falls upon it. Scene appearance modeling is thus necessary for understanding which changes in the appearance of a scene are the result of illumination changes. For any camera, the appearance of the scene is a function of the illumination sources in the scene, the three-dimensional configuration of the objects in the scene and the reflectance properties of all the surfaces in the scene. A scene appearance model is described here as a function of the behavior of static illumination sources, within or beyond the scene, and arbitrary three-dimensional configurations of patches and their reflectance distributions. Based on the suggested model, a spatial prediction technique was developed to predict the appearance of the scene, given a few measurements within it. The scene appearance model and the prediction technique were developed analytically and tested empirically. Two potential applications are briefly explored.  相似文献   
106.
107.
The interaction of γ-glycidoxypropyltrimethoxysilane (GPS) with oxidised aluminium substrates has been investigated in terms of the effect of the drying, or curing, temperature. Samples treated with aqueous solutions of GPS at concentrations of 1,4 and 8% v/v were cured at 25, 50, 93 and 120°C. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to construct adsorption isotherms and determine the thicknesses of the various GPS coatings. A temperature effect induces subtle changes in the structure of the resulting films. The uptake of GPS is increasing with increasing concentration of GPS. The structure of the films changes at a threshold temperature between 50 to 93°C. XPS and ToF-SIMS data both indicate that the interaction of the GPS film on aluminium is different for low and high temperatures drying regimes. Using the Beer-Lambert equation, it was found that increasing the curing temperature leads to the variation of the thickness of silane films. This is interpreted in terms of changes in the crosslink density of the films and in their state of hydration and/or degradation.  相似文献   
108.
109.

Polyvinyl alcohol (PVA)/Carboxymethyl cellulose (CMC)/Manganese dioxide (PVA/CMC/MnO2 NPs) nanocomposite were produced by one-pot laser ablation route. PVA/CMC/MnO2 NPs nanocomposite were prepared with different content of manganese dioxide nanoparticles. The formation of MnO2 is confirmed by appearing diffraction peaks at 2θ?=?26.4°, 28.4°, 37.2°, 42.5°, 56.4°, 72.2° according to JCPDS No. 24-0735 which agreed with previous literature. The increasing of laser ablation time causes a change of all bands intensities. All the above conclusions affirmed the formation of Mn–O and their complexation with PVA/CMC blend. The ultraviolet and visible (UV/Vis.) measurements showed enhanced in the optical properties as the ratio of Manganese dioxide nanoparticles enhanced. The absorption edge is changed towards lower photon energy sides when MnO2 NPs are added to the PVA/CMC. The AC conductivity was enhanced after the addition of MnO2 NPs. The values of the ε′ and ε? of the synthesized samples increased as the ratio of Manganese dioxide nanoparticles increased, which is attributed to an increase in the current films' ion conduction. The obtained results demonstrate the benefits of using MnO2 NPs as a filler to improve polymeric systems and suggest it for optical and electrical applications.

  相似文献   
110.
Reverse osmosis (RO) is an interesting process to eliminate small organic solutes (carboxylic acids and alcohols) from distillery condensates before recycling them into the fermentation step. This work investigates the influence of transmembrane pressure, pH and volume reduction factor (VRF) on the efficiency of reverse osmosis treatment of condensate from distillery stillage concentration at pilot scale using three pre-selected membranes (CPA2 and ESPA2 from Hydranautics, BW30 from DOW). Performances were assessed according to permeate flux, solutes rejection and abatement of fermentation inhibition. Transmembrane pressure increase leads to an increase of these three parameters with a plateau for rejections and abatement at 20 bar; however, in order to comply with membranes manufacturer's recommendations and to limit or delay polarization and fouling, it was decided to keep the permeate flux below a value of 30 L h−1 m−2. This corresponded to a maximum pressure of 10 bar for CPA2 and ESPA2 membranes and 25 bar for BW30 membrane. pH increase leads to a diminution of permeate flux and an increase of carboxylic acids rejection whatever the membrane; nevertheless, no abatement of fermentation inhibition is observed. Increasing VRF provokes a decrease of the permeate flux. Although local rejections are stable, the mean rejection assessed with the raw condensate (feed) and the mean permeate decreases. However, the fermentation inhibition remains under 10% up to a VRF of 8. BW30 membrane exhibits the highest rejections and inhibition abatement. On the basis of the pilot scale results with the BW30 membrane, a preliminary estimation of the membrane area is proposed for an industrial plant with 100 m3 h−1 of condensate flow rate and the optimized parameters (pressure 25 bar, no pH modification, VRF 4 and 8).  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