全文获取类型
收费全文 | 1515篇 |
免费 | 64篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 27篇 |
化学工业 | 536篇 |
金属工艺 | 11篇 |
机械仪表 | 37篇 |
建筑科学 | 52篇 |
能源动力 | 47篇 |
轻工业 | 187篇 |
水利工程 | 7篇 |
石油天然气 | 2篇 |
武器工业 | 1篇 |
无线电 | 111篇 |
一般工业技术 | 214篇 |
冶金工业 | 32篇 |
原子能技术 | 17篇 |
自动化技术 | 299篇 |
出版年
2024年 | 3篇 |
2023年 | 11篇 |
2022年 | 94篇 |
2021年 | 86篇 |
2020年 | 39篇 |
2019年 | 41篇 |
2018年 | 45篇 |
2017年 | 27篇 |
2016年 | 45篇 |
2015年 | 43篇 |
2014年 | 63篇 |
2013年 | 108篇 |
2012年 | 103篇 |
2011年 | 100篇 |
2010年 | 86篇 |
2009年 | 66篇 |
2008年 | 65篇 |
2007年 | 77篇 |
2006年 | 60篇 |
2005年 | 50篇 |
2004年 | 44篇 |
2003年 | 44篇 |
2002年 | 36篇 |
2001年 | 21篇 |
2000年 | 20篇 |
1999年 | 22篇 |
1998年 | 18篇 |
1997年 | 18篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 10篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1973年 | 2篇 |
1971年 | 3篇 |
1967年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有1580条查询结果,搜索用时 15 毫秒
91.
Pianetti A Manti A Boi P Citterio B Sabatini L Papa S Rocchi MB Bruscolini F 《International journal of food microbiology》2008,127(3):252-260
Aeromonads in waters and foods can represent a risk to human health. Factors such as sodium chloride concentration and temperature can affect growth and viability of several food and water-borne pathogens. The behaviour of an Aeromonas hydrophila strain in the presence of 1.7%, 3.4% and 6% NaCl concentrations at 24 degrees C and 4 degrees C was studied over a 188 day period. Viability and membrane potential were assessed by flow cytometry; growth was evaluated by plate count technique. Flow cytometry evidenced that A. hydrophila retained viability over the period although varying according to temperature and salt concentrations. Colony Forming Units were generally lower in number than viable cells especially in the presence of 6% NaCl, indicating the occurrence of stressed cells which maintain metabolic activity yet are not able to grow on agar plates. In conclusion, A. hydrophila showed a long-term halotolerance even at elevated (6%) NaCl concentrations and a lesser sensitivity to salt at low temperature; therefore, low temperature and salt, which are two important factors limiting bacterial growth, do not assure safety in the case of high initial contamination. Finally, cytometry appears a valid tool for the rapid detection of the viability of pathogenic bacteria in food and environmental matrices to control and prevent health risks. 相似文献
92.
Gabriele Dono Raffaele Cortignani Luca Doro Luca Giraldo Luigi Ledda Massimiliano Pasqui Pier Paolo Roggero 《Water Resources Management》2013,27(10):3607-3622
Climate change is likely to have a profound effect on many agricultural variables, although the extent of its influence will vary over the course of the annual farm management cycle. Consequently, the effect of different and interconnected physical, technical and economic factors must be modeled in order to estimate the effects of climate change on agricultural productivity. Such modeling commonly makes use of indicators that summarize the among environmental factors that are considered when farmers plan their activities. This study uses net evapotranspiration (ETN), estimated using EPIC, as a proxy index for the physical factors considered by farmers when managing irrigation. Recent trends suggest that the probability distribution function of ETN may continue to change in the near future due to changes in the irrigation needs of crops. Also, water availability may continue to vary due to changes in the rainfall regime. The impacts of the uncertainties related to these changes on costs are evaluated using a Discrete Stochastic Programming model representing an irrigable Mediterranean area where limited water is supplied from a reservoir. In this context, adaptation to climate change can be best supported by improvements to the collective irrigation systems, rather than by measures aimed at individual farms such as those contained within the rural development policy. 相似文献
93.
In this report is described the preparation of six nanocomposite membranes of formula {Nafion/[(ZrO2)⋅(SiO2)0.67]ΨZrO2} with ΨZrO2 ranging from 0 to 1.79 based on Nafion® and [(ZrO2)·(SiO2)0.67] nanofiller. Morphology investigations carried out by SEM measurements indicate that the composition of membranes is asymmetric. Indeed, with respect to the direction of the films after casting procedure, the top side (A-side) and bottom side (B-side) present a different nanofiller concentration. The concentration of nanofiller increases gradually from A to B side. The membranes present thicknesses ranging from 170 to 350 nm and are studied by FT-IR ATR and micro-Raman measurements. 相似文献
94.
In this paper, we present a novel wavelet-based compression algorithm for multiview images. This method uses a layer-based representation, where the 3-D scene is approximated by a set of depth planes with their associated constant disparities. The layers are extracted from a collection of images captured at multiple viewpoints and transformed using the 3-D discrete wavelet transform (DWT). The DWT consists of the 1-D disparity compensated DWT across the viewpoints and the 2-D shape-adaptive DWT across the spatial dimensions. Finally, the wavelet coefficients are quantized and entropy coded along with the layer contours. To improve the rate-distortion performance of the entire coding method, we develop a bit allocation strategy for the distribution of the available bit budget between encoding the layer contours and the wavelet coefficients. The achieved performance of our proposed scheme outperforms the state-of-the-art codecs for several data sets of varying complexity. 相似文献
95.
This article addresses the problem of detecting feature interactions in the area of telephony systems design. The proposed approach consists of two phases: filtering and testing. The filtering phase detects possible interactions by identifying incoherencies in a logic specification of the main elements of the features, consisting of preconditions, triggers, results and constraints. If incoherencies are identified, then an interaction is suspected, test cases corresponding to the suspected interaction are generated and testing is applied to see if the interaction actually exists. Two case studies, carried out on established benchmarks, show that this approach gives good results in practice.
Nicolas Gorse received a Master of Computer Science from the University of Ottawa, School of Information Technology and Engineering in 2001.He is currently a Ph.D. candidate in the Département d'Informatique et Recherche Opérationnelle of the Université de Montréal. His research interests relate to formal methods and their application in the design and verification of complex electronic systems at high levels of abstraction.
Luigi Logrippo received a degree in law from the University of Rome (Italy) in 1961, and in the same year he started a career in computing. He worked for several computer companies and in 1969 he obtained a Master of Computer Science from the University of Manitoba, followed by a Ph.D. of Computer Science from the University of Waterloo in 1974.He was with the University of Ottawa for 29 years, where he was Chair of the Computer Science Department for 7 years. In 2002 he moved to the Université du Québec en Outaouais, Département d'Informatique et Ingénierie, while remaining associated with the University of Ottawa as an Adjunct Professor.His interest area is formal and logic-based methods and their applications in the design of communications systems. For a number of years he worked on the development of tools and methods for the language LOTOS. Current research deals with the formal analysis of advanced communications services made possible by internet telephony, of the policies that govern them, and of their interactions, in application areas such as presence features and e-commerce contracts.
Jacques Sincennes is a research programmer/systems analyst at the University of Ottawa, School of Information Technology and Engineering. He has held this position for the past 17 years. He is coauthor of a number of papers and a patent application.An erratum to this article is available at . 相似文献
96.
97.
Gian Carlo Alfonso Luigi Olivero Antonio Turturro Enrico Pedemonte 《Polymer International》1973,5(2):141-154
The self-seeding crystallisation technique is applied to a dilute solution of polyethylene in xylene containing, in suspension, foreign particles; data concerning some pigments usually employed for colouring the plastics are reported. It is shown that this method allows easy demonstration of the interactions existing between the dissolved polymer and the pigment; at the same time, it is possible to study the morphology which is evolved as a consequence of these interactions under particularly simple conditions as only a small amount of polymer crystallises on the pigment particles. The behaviour of several pigments is consistent with the results obtained by crystallising the bulk polyethylene coloured with the same pigments. Some unusual morphologies are made evident. 相似文献
98.
Bedini Luigi Bramanti Mauro Denoth F. 《IEEE transactions on bio-medical engineering》1980,(11):623-630
In this paper the electromagnetic interaction between a resonator and a lossy dielectric body is examined by means of a simple model suitable for computer simulation; the body was assumed to have a revolution form and the resonator was electromagnetic coupled to the body by its inductive element constituted by a planar circular or spiral coil. On the basis of the model a computer program was derived which allows a simple numerical evaluation of the variation in the resonant frequency caused by the interaction mentioned above. 相似文献
99.
Luigi Sedda David W. Morley David Benz G. R. William Wint Zhengming Wan David J. Rogers 《International journal of remote sensing》2013,34(4):1220-1233
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra and Aqua satellites conducts continuous monitoring of the Earth's land surface and oceans. Recently, a sharp discontinuity (averaging 1.9°C) has been noticed at 60° N in both MODIS daytime and night-time land surface temperature (LST) products. This linear artefact arises because the CO2 high cloud test in the operational code for the generation of the MODIS cloud mask product is used only in the non-polar region (between 60° N and 60° S). The resulting discontinuity clearly has negative implications for any statistical applications of these temperature data. In this technical note we present a new algorithm, which minimizes this discontinuity. The method uses edge detection and elimination based on a mixture of Sobel and non-linear Laplacian filters (edge detection and quantification), cubic splines (edge modelling), and a controllable power function for image restoration. The implementation of this algorithm is demonstrated on an image of average minimum night-time LST between 2001 and 2008. 相似文献
100.