全文获取类型
收费全文 | 3818篇 |
免费 | 203篇 |
国内免费 | 35篇 |
专业分类
电工技术 | 60篇 |
综合类 | 67篇 |
化学工业 | 830篇 |
金属工艺 | 165篇 |
机械仪表 | 151篇 |
建筑科学 | 201篇 |
矿业工程 | 42篇 |
能源动力 | 247篇 |
轻工业 | 524篇 |
水利工程 | 22篇 |
石油天然气 | 38篇 |
武器工业 | 2篇 |
无线电 | 210篇 |
一般工业技术 | 573篇 |
冶金工业 | 352篇 |
原子能技术 | 48篇 |
自动化技术 | 524篇 |
出版年
2024年 | 20篇 |
2023年 | 41篇 |
2022年 | 75篇 |
2021年 | 108篇 |
2020年 | 136篇 |
2019年 | 119篇 |
2018年 | 164篇 |
2017年 | 146篇 |
2016年 | 175篇 |
2015年 | 101篇 |
2014年 | 168篇 |
2013年 | 387篇 |
2012年 | 203篇 |
2011年 | 207篇 |
2010年 | 174篇 |
2009年 | 220篇 |
2008年 | 175篇 |
2007年 | 159篇 |
2006年 | 126篇 |
2005年 | 82篇 |
2004年 | 94篇 |
2003年 | 116篇 |
2002年 | 161篇 |
2001年 | 126篇 |
2000年 | 64篇 |
1999年 | 55篇 |
1998年 | 131篇 |
1997年 | 73篇 |
1996年 | 52篇 |
1995年 | 29篇 |
1994年 | 28篇 |
1993年 | 15篇 |
1992年 | 10篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1976年 | 5篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1965年 | 3篇 |
排序方式: 共有4056条查询结果,搜索用时 15 毫秒
51.
高性能混凝土配合比设计的试验研究 总被引:2,自引:0,他引:2
从对HPC组成、结构的认识出发,借鉴利用拨开系数求砂率的方法,提出了一种新的HPC配制方法,并通过试验证实该方法是完全可行的. 相似文献
52.
杨冠鲁 《计算机测量与控制》2003,11(5):354-355,358
文中就无刷柴油发电机的两个输入量,设计了基于单个神经元的双PSD控制器,其智能控制方法简单,响应速度快,MATLAB仿真结果表明,这种控制器对于非线性被控系统具有良好的适应性和鲁棒性. 相似文献
53.
54.
55.
We formulate the signal-to-noise ratio (SNR) for free-space optical links. Upon inserting typical operating parameters, it is seen that SNR well approximates to the inverse of aperture averaged scintillation parameter. By adopting a common source beam power of 10 mW, we select three different source sizes of Gaussian, annular Gaussian (AG), and cosh-Gaussian beams. We then evaluate the SNR of these beams. Our results indicate that when fixed aperture opening is used, fully and partially coherent beams yield almost the same SNR performance. On the other hand, however, focusing and lowering wavelength of operation appear to be quite instrumental in improving the SNR performance. In this context, medium-sized AGB seems to exhibit the best performance. 相似文献
56.
Tankut Atan Olgu Pelin Hüseyinoǧlu 《International Transactions in Operational Research》2017,24(3):465-484
Assignment decisions of referees to football (soccer) games are highly debated in sports media. Referee assignments are typically done on a weekly basis as the league progresses. However, this practice ignores important workload constraints on referees. Moreover, referees' skill levels should also be considered in determining their assignments. In this article, we first give a mixed integer linear program formulation for the problem of simultaneously generating a game schedule and assigning main referees to games by incorporating specific rules in the Turkish league. We also approach this problem using a genetic algorithm (GA) because of the computational difficulties in solving the problem. In the GA solution pool, we suggest using templates for referee assignments that follow several referee‐related workload constraints. We explain how these templates can be obtained by solving a mixed integer linear model prior to running the GA. The usage of these templates for referee assignments is conceptually similar to using a basic match schedule for game scheduling such as the one used in the Turkish Football League. We use the Turkish Football League fixtures for 2010–2013 as a case study. Experiments with the GA using real‐world data show a rather modest performance in terms of computation time and objective function value. Our numerical results indicate that the problem is extremely hard to solve. 相似文献
57.
Buğra Gedik 《International journal of parallel programming》2013,41(5):595-620
In recent times, large high-dimensional datasets have become ubiquitous. Video and image repositories, financial, and sensor data are just a few examples of such datasets in practice. Many applications that use such datasets require the retrieval of data items similar to a given query item, or the nearest neighbors (NN or $k$ -NN) of a given item. Another common query is the retrieval of multiple sets of nearest neighbors, i.e., multi $k$ -NN, for different query items on the same data. With commodity multi-core CPUs becoming more and more widespread at lower costs, developing parallel algorithms for these search problems has become increasingly important. While the core nearest neighbor search problem is relatively easy to parallelize, it is challenging to tune it for optimality. This is due to the fact that the various performance-specific algorithmic parameters, or “tuning knobs”, are inter-related and also depend on the data and query workloads. In this paper, we present (1) a detailed study of the various tuning knobs and their contributions on increasing the query throughput for parallelized versions of the two most common classes of high-dimensional multi-NN search algorithms: linear scan and tree traversal, and (2) an offline auto-tuner for setting these knobs by iteratively measuring actual query execution times for a given workload and dataset. We show experimentally that our auto-tuner reaches near-optimal performance and significantly outperforms un-tuned versions of parallel multi-NN algorithms for real video repository data on a variety of multi-core platforms. 相似文献
58.
We address the symmetric flip problem that is inherent to multi‐resolution isometric shape matching algorithms. To this effect, we extend our previous work which handles the dense isometric correspondence problem in the original 3D Euclidean space via coarse‐to‐fine combinatorial matching. The key idea is based on keeping track of all optimal solutions, which may be more than one due to symmetry especially at coarse levels, throughout denser levels of the shape matching process. We compare the resulting dense correspondence algorithm with state‐of‐the‐art techniques over several 3D shape benchmark datasets. The experiments show that our method, which is fast and scalable, is performance‐wise better than or on a par with the best performant algorithms existing in the literature for isometric (or nearly isometric) shape correspondence. Our key idea of tracking symmetric flips can be considered as a meta‐approach that can be applied to other multi‐resolution shape matching algorithms, as we also demonstrate by experiments. 相似文献
59.
This paper presents both a calculus for stream processing, named Brooklet, and its realization as an intermediate language, named River. Because River is based on Brooklet, it has a formal semantics that enables reasoning about the correctness of source translations and optimizations. River builds on Brooklet by addressing the real‐world details that the calculus elides. We evaluated our system by implementing front‐ends for three streaming languages, and three important optimizations, and a back‐end for the System S distributed streaming runtime. Overall, we significantly lower the barrier to entry for new stream‐processing languages and thus grow the ecosystem of this crucial style of programming. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
60.