全文获取类型
收费全文 | 961篇 |
免费 | 84篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 20篇 |
综合类 | 1篇 |
化学工业 | 240篇 |
金属工艺 | 17篇 |
机械仪表 | 25篇 |
建筑科学 | 38篇 |
矿业工程 | 6篇 |
能源动力 | 26篇 |
轻工业 | 94篇 |
水利工程 | 7篇 |
无线电 | 87篇 |
一般工业技术 | 182篇 |
冶金工业 | 20篇 |
原子能技术 | 23篇 |
自动化技术 | 261篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 43篇 |
2021年 | 67篇 |
2020年 | 46篇 |
2019年 | 32篇 |
2018年 | 34篇 |
2017年 | 39篇 |
2016年 | 47篇 |
2015年 | 34篇 |
2014年 | 47篇 |
2013年 | 70篇 |
2012年 | 66篇 |
2011年 | 76篇 |
2010年 | 51篇 |
2009年 | 58篇 |
2008年 | 53篇 |
2007年 | 27篇 |
2006年 | 44篇 |
2005年 | 29篇 |
2004年 | 19篇 |
2003年 | 21篇 |
2002年 | 22篇 |
2001年 | 14篇 |
2000年 | 6篇 |
1999年 | 13篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有1047条查询结果,搜索用时 15 毫秒
71.
Rulon Linford Riccardo Betti Jill Dahlburg James Asay Michael Campbell Phillip Colella Jeffrey Freidberg Jeremy Goodman David Hammer Joseph Hoagland Steve Jardin John Lindl Grant Logan Keith Matzen Gerald Navratil Arthur Nobile John Sethian John Sheffield Mark Tillack Jon Weisheit 《Journal of Fusion Energy》2003,22(2):93-126
This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from Dr. Ray Orbach (Appendix A). In that letter, Dr. Orbach asked FESAC for an assessment of the present status of inertial fusion energy (IFE) research carried out in contributing programs. These programs include the heavy ion (HI) beam, the high average power laser (HAPL), and Z-Pinch drivers and associated technologies, including fast ignition (FI). This report, presented to FESAC on March 29, 2004, and subsequently approved by them (Appendix B), presents FESAC's response to that charge. 相似文献
72.
General schema theory for genetic programming with subtree-swapping crossover: part I 总被引:2,自引:0,他引:2
This is the first part of a two-part paper which introduces a general schema theory for genetic programming (GP) with subtree-swapping crossover. The theory is based on a Cartesian node reference system which makes it possible to describe programs as functions over the space N(2) and allows one to model the process of selection of the crossover points of subtree-swapping crossovers as a probability distribution over N(4). In Part I, we present these notions and models and show how they can be used to calculate useful quantities. In Part II we will show how this machinery, when integrated with other definitions, such as that of variable-arity hyperschema, can be used to construct a general and exact schema theory for the most commonly used types of GP. 相似文献
73.
74.
Marco Gabella Riccardo Notarpietro Stefano Turso Giovanni Perona 《International journal of remote sensing》2013,34(10):2869-2878
A computer program for meteorological radar siting, previously developed for pencil‐beam antenna, long‐range, C‐band radars, has been adapted for fan‐beam antenna, short‐range, X‐band radars. The simulator uses topographic information in the form of a raster digital elevation model and a surface backscattering cross‐section per unit area at grazing angles derived from the literature. It is independent of specific radar sites and radar systems. Its use will enhance optimized scanning strategies, antenna design tailored to mountainous terrain and knowledge of land‐clutter measurements at low grazing angles. The raster‐based approach used in implementing the program makes it compatible with any desired spatial resolution. Simplicity and short simulation times have been pursued as primary goals during the planning and implementation phases of the routines. A preliminary validation of the simulator using backscattering data acquired in the Alps is presented in this letter. 相似文献
75.
Gaia Vaglio Laurin Fabio Del Frate Luca Pasolli Claudia Notarnicola Leila Guerriero Riccardo Valentini 《International journal of remote sensing》2013,34(19):6898-6913
Natural vegetation monitoring in the alpine mountain range is a priority in the European Union in view of climate change effects. Many potential monitoring tools, based on advanced remote sensing sensors, are still not fully integrated in operational activities, such as those exploiting very high-resolution synthetic aperture radar (SAR) or light detection and ranging (lidar) data. Their testing is important for possible incorporation in routine monitoring and to increase the quantity and quality of environmental information. In this study the potential of ALOS PALSAR and RADARSAT-2 SAR scenes' synergic use for discrimination of different vegetation types was tested in an alpine heterogeneous and fragmented landscape. The integration of a lidar-based canopy height model (CHM) with SAR data was also tested. A SPOT image was used as a benchmark to evaluate the results obtained with different input data. Discrimination of vegetation types was performed with maximum likelihood classification and neural networks. Six tested data combinations obtained more than 85% overall accuracy, and the most complex input which integrates the two SARs with lidar CHM outperformed the result based on SPOT. Neural network algorithms provided the best results. This study highlights the advantages of integrating SAR sensors with lidar CHM for vegetation monitoring in a changing environment. 相似文献
76.
Throughout much of the modern period, the human mind has been regarded as a property of the brain and therefore something confined to the inside of the head—a view commonly known as ‘internalism’. But recent works in cognitive science, philosophy, and anthropology, as well as certain trends in the development of technology, suggest an emerging view of the mind as a process not confined to the brain but spread through the body and world—an outlook covered by a family of views labelled ‘externalism’. In this paper, we will suggest there is now sufficient momentum in favour of externalism of various kinds to mark a historical shift in the way the mind is understood. We dub this emerging externalist tendency the ‘New Mind’. Key properties of the New Mind will be summarised and some of its implications considered in areas such as art and culture, technology, and the science of consciousness. 相似文献
77.
In Very Long Baseline Interferometry, signals from far radio sources are simultaneously recorded at different antennas, with the purpose of investigating their physical properties. The recorded signals are generally modeled as realizations of Gaussian processes, whose power is dominated by the system noise at the receiving antennas. The actual signal coming from the radio source can be detected only after cross-correlation of the various data-streams. The signals received at each antenna are digitized after low noise amplification and frequency down-conversion, in order to allow subsequent digital post-processing. The applied quantization is coarse, 1 or 2 bits being generally associated to the signal amplitude. In modern applications the sampling is typically performed at a high rate, and subchannels are then generated by filtering, followed by decimation and requantization of the signal streams. The redigitized streams are then cross-correlated to extract the physical observables. While the classical effect of quantization has widely been studied in the past, the decorrelation induced by the filtering and requantization process is still characterized experimentally, mainly due to its inherent mathematical complexity. In the present work we analyze the above problem, and provide algorithms and analytical formulas aimed at predicting the induced decorrelation for a wide class of quantization schemes, with the unique assumption of weakly correlated signals, typically fulfilled in VLBI and radio astronomy applications. 相似文献
78.
In this paper, we study thermal-constrained hard real-time systems, where real-time guarantees must be met without exceeding
safe temperature levels within the processor. Dynamic speed scaling is one of the major techniques to manage power so as to
maintain safe temperature levels. As example, we adopt a reactive speed control technique in our work. We design an extended
busy-period analysis methodology to perform schedulability analysis for general task arrivals under reactive speed control
with First-In-First-Out (FIFO), Static-Priority (SP), and Earliest-Deadline-First (EDF) scheduling. As a special case, we
obtain a closed-form formula for the worst-case response time of jobs under the leaky-bucket task arrival model. Our data
show how reactive speed control can decrease the worst-case response time of tasks in comparison with any constant-speed scheme. 相似文献
79.
Gianni Costa Giuseppe Manco Riccardo Ortale Ettore Ritacco 《Knowledge and Information Systems》2011,33(1):137-169
We propose two models for improving the performance of rule-based classification under unbalanced and highly imprecise domains. Both models are probabilistic frameworks aimed to boost the performance of basic rule-based classifiers. The first model implements a global-to-local scheme, where the response of a global rule-based classifier is refined by performing a probabilistic analysis of the coverage of its rules. In particular, the coverage of the individual rules is used to learn local probabilistic models, which ultimately refine the predictions from the corresponding rules of the global classifier. The second model implements a dual local-to-global strategy, in which single classification rules are combined within an exponential probabilistic model in order to boost the overall performance as a side effect of mutual influence. Several variants of the basic ideas are studied, and their performances are thoroughly evaluated and compared with state-of-the-art algorithms on standard benchmark datasets. 相似文献
80.
Fabio Rizzo Francesco Meinardi Riccardo Tubino Roberto Pagliarin Giovanna Dellepiane Antonio Papagni 《Synthetic Metals》2009,159(5-6):356-360
The synthesis of a new DO3A-based macrocyclic ligand bearing a 8-hydroxyquinoline residue together with the preparation of its Eu3+ and Er3+ neutral complexes are described. In a previous report [F. Rizzo, A. Papagni, F. Meinardi, R. Tubino, M. Ottonelli, G.F. Musso, G. Dellepiane, Synth. Met. 147 (2004) 143], we have shown that lanthanide complexes display very high stability combined with a good luminescence in aqueous solution under UV radiation, which indicate an energy transfer process from the excited 8-hydroxyquinoline moiety to the metal. In this work, we correlate the ability to transfer the energy from the sensitizer to lanthanide ion with pH behaviour of the antenna. Furthermore, the variation of pH in Eu3+ complex supports the hypothesis of presence of charge-transfer transitions. The good solubility and sensitized emission in different solvents (organic and water) are very important aspects for their technologic applications as luminescent probes or NIR-emitting devices. 相似文献