全文获取类型
收费全文 | 4123篇 |
免费 | 252篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 49篇 |
综合类 | 5篇 |
化学工业 | 1131篇 |
金属工艺 | 68篇 |
机械仪表 | 113篇 |
建筑科学 | 208篇 |
矿业工程 | 8篇 |
能源动力 | 152篇 |
轻工业 | 505篇 |
水利工程 | 25篇 |
石油天然气 | 13篇 |
无线电 | 276篇 |
一般工业技术 | 714篇 |
冶金工业 | 159篇 |
原子能技术 | 45篇 |
自动化技术 | 908篇 |
出版年
2024年 | 7篇 |
2023年 | 31篇 |
2022年 | 137篇 |
2021年 | 215篇 |
2020年 | 100篇 |
2019年 | 114篇 |
2018年 | 154篇 |
2017年 | 136篇 |
2016年 | 192篇 |
2015年 | 112篇 |
2014年 | 171篇 |
2013年 | 306篇 |
2012年 | 283篇 |
2011年 | 335篇 |
2010年 | 220篇 |
2009年 | 252篇 |
2008年 | 233篇 |
2007年 | 188篇 |
2006年 | 194篇 |
2005年 | 154篇 |
2004年 | 111篇 |
2003年 | 98篇 |
2002年 | 80篇 |
2001年 | 60篇 |
2000年 | 58篇 |
1999年 | 55篇 |
1998年 | 58篇 |
1997年 | 40篇 |
1996年 | 39篇 |
1995年 | 40篇 |
1994年 | 20篇 |
1993年 | 25篇 |
1992年 | 10篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 12篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 16篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1973年 | 3篇 |
排序方式: 共有4379条查询结果,搜索用时 250 毫秒
991.
Aurora Barrero Xabiel G. Pañeda Roberto García Sergio Cabrero 《International journal of human-computer interaction》2013,29(3):210-225
Remote controls are especially problematic for writing text, something necessary in many interactive digital TV applications (IDTV). In the context of research aimed at finding effective entry methods for IDTV applications, an empirical investigation was carried out and is presented in this article. The study analyzed the errors committed by 82 users in an experiment in which they wrote 7,395 sentences. Several typing methods suitable for IDTV contexts were used for experimentation. There were 3,562 of the sentences that registered at least one error. These errors were classified and their main causes analyzed, the particular characteristics of the users taken into account. The results show that the most frequent errors are proximity mistakes in all the evaluated methods. They appear in between 13.75% and 32.31% of the sentences, depending on the input method. Also, age and background are major aspects affecting the number and type of mistakes. The results could be the basis of changes in the design of conventional remote controls or in the design of advanced techniques for error recognition and correction. 相似文献
992.
Roberto Best B. Juan M. Aceves H. Jorge M. Islas S. Fabio L. Manzini P. Isaac Pilatowsky F. Rossano Scoccia Mario Motta 《Applied Thermal Engineering》2013,50(2):1447-1452
In Mexico efforts are being made to promote the use of solar energy for cooling in the Agro-Food Industries (AFI), 120 industries were contacted in order to assess the solar cooling potential application in the sector. One case study was selected among the visited potential end users according to the size of the facility, the information available and their willingness to collaborate in the present project. Data from the industry was used to select the appropriate solar cooling concept and therefore the collector’s typology, and the absorption cooling system. Moreover, the operation of the system was simulated in order to define the optimal size of the collector field required. The proposed cooling system was composed by a Fresnel concentrating collector field to activate a series of air cooled single-effect ammonia–water absorption chillers. The cooling system simulation was carried out with the Transient Systems Simulation Programme (TRNSYS) which allowed to model the collector system that fulfill the required load. The calculated saved electricity was around 19% of the total consumption, this small fraction is due to the fact that the selected facility is operating continuously with very large refrigeration capacities. The specifications of the simulated solar cooling system are presented. 相似文献
993.
Claudia Canedoli Francesco Crocco Roberto Comolli Emilio Padoa-Schioppa 《Landscape Research》2018,43(5):632-651
Spatial expansion of cities appears to be unavoidable. Despite concern around landscape alterations caused by urban expansion, the understanding of the amounts and patterns of this phenomenon is sorely lacking. In this study, we quantified the current pattern of landscape fragmentation in the urban region (UR) of Milan and analysed the trend of urban sprawl over more than 50 years. The UR of Milan was spatially defined using a standardised and repeatable methodology that combines land-use and population density data. Fragmentation was assessed using the effective mesh size (meff). The trend of sprawl was monitored between 1954 and 2012 and over different areas to detect the magnitude (amount and direction) and patterns of changes. Results revealed a positive trend and a high degree of sprawl over the whole study area. 相似文献
994.
Gustaf Larsson Per Johan Gustafsson Roberto Crocetti 《Holz als Roh- und Werkstoff》2018,76(2):401-411
The load capacity of long adhesive lap joints is often governed by stress concentrations at the lap ends. This paper investigates a method to minimize these stress concentrations by using a bond line with low shear stiffness and sufficient strength, here denoted as a resilient bond line. The resilient bond line is intended to increase the load carrying capacity of long lap joints by achieving a more uniform shear stress distribution while maintaining an elastic joint behaviour without damage or plastic deformation. The study comprises analytical, numerical and full-sized experimental work on double lap joints with lengths 200–700 mm comparing conventional stiff bond lines to resilient bond lines. Different resilient bonds lines were obtained by using rubber-like adhesives and by having a rubber mat within the bond line. An analytical definition of a ‘long’ lap joint is suggested and a study of adhesive-rubber bonding is also presented. The numerical analysis clearly indicates that an increase in load carrying capacity is made possible using resilient bond lines. A good agreement is also found between the numerical results and the analytical Volkersen theory, indicating that reasonable strength predictions can be obtained by hand calculations if the joint is designed in order to minimize the influence of peel stress. The experimental results of the resilient bond line verify the numerical findings, although production difficulties decrease the statistical significance of the result. On the contrary, the experimental results of the conventional bond lines significantly exceeded the numerical predictions, showing similar load carrying capacities to the resilient bond line. This is probably due to the specific boundary conditions used in the test setup. Despite some contradictory experimental results, the conclusion of this study is that the efficiency of long lap joints can be increased by the use of a bond line with low shear stiffness and sufficient strength. 相似文献
995.
In this discussion we review the main remarks of Laviolette, Seaman, Barrett, and Woodall. First, we examine how the subjectivist view of probability faces the task of modeling human reasoning according to a cognitive viewpoint. We then investigate the nature of the fuzzy and probabilistic controllers analyzed by the authors, refuting the hypothesis of similarity. We show that, due to the different theoretical basis, the representativeness of the fuzzy controller overcomes the probabilistic controller in resembling the expert's knowledge. We also review the authors'comparison between the fuzzy and probabilistic approaches to monitor multinomial processes, emphasizing biases and misconceptions in the authors' analysis. 相似文献
996.
997.
998.
Giovanni Ambrosi Simona Bartocci Laurent Basara Roberto Battiston William J. Burger Luca Carfora Guido Castellini Piero Cipollone Livio Conti Andrea Contin Cinzia De Donato Cristian De Santis Francesco M. Follega Cristina Guandalini Maria Ionica Roberto Iuppa Giuliano Laurenti Ignazio Lazzizzera Mauro Lolli Christian Manea Laura Marcelli Giuseppe Masciantonio Matteo Mergé Giuseppe Osteria Lorenzo Pacini Francesco Palma Federico Palmonari Beatrice Panico Laura Patrizii Francesco Perfetto Piergiorgio Picozza Michele Pozzato Matteo Puel Irina Rashevskaya Ester Ricci Marco Ricci Sergio Bruno Ricciarini Valentina Scotti Alessando Sotgiu Roberta Sparvoli Bruno Spataro Vincenzo Vitale 《中国科学:技术科学(英文版)》2018,61(5):643-652
CSES(China Seismo-Electromagnetic Satellite) is a mission developed by CNSA(Chinese National Space Administration) and ASI(Italian Space Agency), to investigate the near-Earth electromagnetic, plasma and particle environment, for studying the seismo-associated disturbances in the ionosphere-magnetosphere transition zone. The anthropogenic and electromagnetic noise,as well as the natural non-seismic electromagnetic emissions is mainly due to tropospheric activity. In particular, the mission aims to confirming the existence of possible temporal correlations between the occurrence of earthquakes for medium and strong magnitude and the observation in space of electromagnetic perturbations, plasma variations and precipitation of bursts with highenergy charged particles from the inner Van Allen belt. In this framework, the high energy particle detector(HEPD) of the CSES mission has been developed by the Italian LIMADOU Collaboration. HEPD is an advanced detector based on a tower of scintillators and a silicon tracker that provides good energy and angular resolution and a wide angular acceptance, for electrons of 3–100 Me V, protons of 30–200 Me V and light nuclei up to the oxygen. CSES satellite has been launched on February 2~(nd), 2018 from the Jiuquan Satellite Launch Center(China). 相似文献
999.
David H. Allen Roberto F. Soares Curtis Berthelot 《International Journal of Pavement Engineering》2017,18(4):309-320
A computational multi-scale procedure for designing flexible pavement is developed in this, the first of a three part series. In this paper, computational analyses are performed on sequentially larger length scales, termed expanding multi-scaling. The model is constructed by the finite element method at each length scale, thereby creating a one-way coupled multi-scale algorithm that is capable of accounting for the effects of variations in design parameters at each length scale on the performance of flexible pavements. For example, the algorithm can be utilised to predict the effects of small-scale design variables such as volume fractions of additives, fines and aggregate, as well as the effects of large-scale design variables such as asphalt concrete thickness and degree of base layer compaction on rutting due to cyclic loading. The computational procedure is briefly herein, including the experimental properties required to deploy the computational scheme for the purpose of pavement design. The paper concludes with several demonstrative examples intended to elucidate the power of this predictive technology for the purpose of designing more sustainable pavements. 相似文献
1000.
Cibele Tosin Sílvio Roberto Andrietta Maria da Graa Stupiello Andrietta 《Journal of the Institute of Brewing》2015,121(3):343-348
Seeking to understand the dynamics of the yeast population in a bioethanol fermentation process that uses cell recycling, the yeast inhabiting the fermentation tanks throughout the production season were monitored. A total of 26 yeasts were isolated from tanks in a Brazilian bioethanol distillery plant during six different periods of the season. These yeasts were evaluated with regard to fermentative capacity and all yeasts were qualified to be used for bioethanol production. Based on the numerical taxonomy, it was possible to say that they were all representative of Saccharomyces sensu stricto. A total of 10 different banding patterns were obtained from the 16 strains isolated. This work has shown that the yeast introduced at the beginning of the season was quickly replaced by one or more native yeast strains. It was also shown that the replacement of these strains is not always harmful to the process and isolating such yeasts found in the fermentation tanks could be an interesting strategy for new strain selection. Copyright © 2015 The Institute of Brewing & Distilling 相似文献