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   6129篇
  免费   256篇
  国内免费   299篇
电工技术   249篇
综合类   244篇
化学工业   400篇
金属工艺   246篇
机械仪表   521篇
建筑科学   358篇
矿业工程   123篇
能源动力   322篇
轻工业   219篇
水利工程   76篇
石油天然气   89篇
武器工业   28篇
无线电   364篇
一般工业技术   423篇
冶金工业   163篇
原子能技术   55篇
自动化技术   2804篇
  2024年   4篇
  2023年   107篇
  2022年   109篇
  2021年   202篇
  2020年   185篇
  2019年   140篇
  2018年   107篇
  2017年   148篇
  2016年   198篇
  2015年   194篇
  2014年   273篇
  2013年   361篇
  2012年   258篇
  2011年   400篇
  2010年   282篇
  2009年   341篇
  2008年   339篇
  2007年   380篇
  2006年   341篇
  2005年   335篇
  2004年   267篇
  2003年   239篇
  2002年   209篇
  2001年   175篇
  2000年   149篇
  1999年   158篇
  1998年   154篇
  1997年   119篇
  1996年   85篇
  1995年   90篇
  1994年   67篇
  1993年   64篇
  1992年   42篇
  1991年   25篇
  1990年   23篇
  1989年   21篇
  1988年   8篇
  1987年   11篇
  1986年   10篇
  1985年   13篇
  1984年   4篇
  1983年   7篇
  1981年   3篇
  1980年   3篇
  1979年   5篇
  1974年   2篇
  1967年   3篇
  1966年   4篇
  1965年   6篇
  1956年   2篇
排序方式: 共有6684条查询结果,搜索用时 15 毫秒
1.
In the present investigation, systematic grinding experiments were conducted in a laboratory ball mill to determine the breakage properties of low-grade PGE bearing chromite ore. The population balance modeling technique was used to study the breakage parameters such as primary breakage distribution (Bi, j) and the specific rates of breakage (Si). The breakage and selection function values were determined for six feed sizes. The results stated that the breakage follows the first-order grinding kinetics for all the feed sizes. It was observed that the coarser feed sizes exhibit higher selection function values than the finer feed size. Further, an artificial neural network was used to predict breakage characteristics of low-grade PGE bearing chromite ore. The predicted results obtained from the neural network modeling were close to the experimental results with a correlation of determination R2 = 0.99 for both product size and selection function.  相似文献   
2.
《Ceramics International》2022,48(10):13754-13760
With the development of science and technology, artificial neural networks (ANNs) have become a research spot. Furthermore, two-terminal oxide memristors with adjustable resistance have attracted extensive attention due to their simple structure, low power consumption, and easy integration, among other attractive features. Additionally, among many oxides, ceria has exhibited good performance, such as longer retention and better stability in resistive devices; however, it was currently rarely used in artificial neural synapses. In this work, a self-designed Ag/CeO2/Pt memristor was found to realize the slow transition between the high-resistance state (HRS) and low-resistance state (LRS) at a very small working voltage. It was also found to exhibit very good retention performance and cyclic characteristics. The conductivity of the device was analyzed by the current-voltage (I–V) characteristics curve. Furthermore, its artificial synaptic function was explored, and a series of neuromorphic systems simulations were carried out. Additionally, the relationships between the pulse sequence parameters and the resistance state of the device were explored, and an electrical signal simulation of Pavlov's dog experiment was designed. The findings demonstrated that the device could be used to realize the application of artificial neural synapse simulation.  相似文献   
3.
教学行为分析作是教学质量分析的重要组成部分,也是教学引导与反馈机制的重要依据。文章阐述了人工智能(AI)的含义及发展历程,重点分析总结了教学行为分析方法及AI在教学行为分析上的应用。文章以东南大学电工电子在线实验为研究平台,探索分析了AI技术在实验教学行为分析上的可行性,梳理了基于专家系统的在线实验分析系统的设计思路,充分探讨了“智能”教育在实验教学中的深刻内涵。  相似文献   
4.
《Ceramics International》2022,48(6):7748-7758
Micromechanics model, finite element (FE) simulation of microindentation and machine learning were deployed to predict the mechanical properties of Cu–Al2O3 nanocomposites. The micromechanical model was developed based on the rule of mixture and grain and grain boundary sizes evolution to predict the elastic modulus of the produced nanocomposites. Then, a FE model was developed to simulate the microindentation test. The input for the FE model was the elastic modulus that was computed using the micromechanics model and wide range of yield and tangent stresses values. Finally, the output load-displacement response from the FE model, the elastic modulus, the yield and tangent strengths used for the FE simulations, and the residual indentation depth were used to train the machine learning model (Random vector functional link network) for the prediction of the yield and tangent stresses of the produced nanocomposites. Cu–Al2O3 nanocomposites with different Al2O3 concentration were manufactured using insitu chemical method to validate the proposed model. After training the model, the microindentation experimental load-displacement curve for Cu–Al2O3 nanocomposites was fed to the machine learning model and the mechanical properties were obtained. The obtained mechanical properties were in very good agreement with the experimental ones achieving 0.99 coefficient of determination R2 for the yield strength.  相似文献   
5.
This paper analyses the perception of Artificial Intelligence (AI) by individuals in Spain and the factors associated with it. It uses data from 6308 individuals from a 2018 Spanish survey. A binary logit regression model is formulated and estimated for the attitude towards robots and AI and its possible determinants. As main results are that a gender gap is detected, and that people have a negative attitude if they are not interested in scientific discoveries and technological developments and if AI and robots are not useful at work.  相似文献   
6.
This work presents a pulsatile Zone Model Predictive Control (pZMPC) for the control of blood glucose concentration (BGC) in patients with Type 1 Diabetes Mellitus (T1DM). The main novelties of the algorithm – in contrast to other existing strategies – are: (i) it controls the patient glycemia by injecting short duration insulin boluses for both, the basal and bolus infusions, in an unified manner, (ii) it performs the predictions and estimations (critical to anticipate both, hypo and hyperglycemia) based on a physiological individualized long-term model, (iii) it employs disturbance observers to compensate plant-model mismatches, (iv) it ensures, under standard assumptions, closed-loop stability, and (v) it can be used – under minor modifications – as an optimal basal–bolus calculator to emulate conventional therapies. Because of the latter characteristic, a significantly better performance is achieved, not only in terms of classical indexes (time in the normoglycemia zone, avoidance of hypoglycemia in the short term, avoidance of hyperglycemia in the long term) but also in terms of its applicability (use of the pump or injections). Such a performance is tested in a cohort of in-silico patients from the FDA-accepted UVA/Padova simulation platform, considering the most challenging scenarios.  相似文献   
7.
8.
This paper presents an improved artificial bee colony algorithm. Under the framework of the basic artificial bee colony algorithm, this paper redefines the artificial bee colony and introduces search strategies for group escape and foraging based on Levy flight. The proposed algorithm is named artificial bee colony algorithm based on escaped foraging strategy (EFSABC).There are different strategies for scout bees, onlookers, and free bees searching for honey sources in the EFSABC: all working bees relinquish old honey sources due to disturbance, and select different routines to seek new honey sources. Sixteen typical high-dimensional standard functions are used to verify the effectiveness of the proposed algorithm. The EFSABC algorithm outperforms the traditional artificial bee colony algorithm in all aspects.  相似文献   
9.
The accurate prediction of the visual comfort zone in an indoor environment is difficult as it depends on many parameters. This is especially the case for large compact urban areas in which the density and shadow from neighboring buildings can limit the accessible daylighting in indoor spaces. This paper investigates the satisfaction range for illuminance regarding indoor air temperature in office buildings and the significant parameters affecting this range in six office buildings in Tehran, Iran. Lighting comfort has been evaluated by a subjective survey (509 total responses) and field measurement. The questionnaires were filled out in 146 and 109 rooms in summer and winter, respectively. The results show that the illuminance should not be less than 550 lx, while illuminance between 600 and 650 lx provides the highest satisfaction level. The satisfaction with lighting level is affected by individual parameters such as age, type of activity, and environmental parameters such as window orientation, external obscurations, and season. A relationship was observed between lighting level satisfaction and thermal condition acceptance, and the overall comfort depends more on thermal conditions than the lighting level.  相似文献   
10.
Water oxidation is a key reaction for water splitting. The decomposition of Fe-based-molecular structures toward Fe-based oxides is a promising method for oxygen-evolution reaction (OER) through water oxidation. The decomposition of Fe-based-molecular structures method results in a slow decomposition of precatalysts and forms Fe oxide-based catalysts. In this study, the Fe species formed through the decomposition of a dinuclear Fe(III) complex under OER is investigated by X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and the electrochemical method. In addition, using Ni(OH)2, a new approach is reported for detecting trace Fe species on the electrode surface. The resulting Fe oxide-based catalyst shows a catalytic current with an onset of 621 mV overpotential and the Tafel slope of 113.7 mV/decade at pH 11 in a buffer phosphate.  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