全文获取类型
收费全文 | 6062篇 |
免费 | 364篇 |
国内免费 | 37篇 |
专业分类
电工技术 | 77篇 |
综合类 | 67篇 |
化学工业 | 1279篇 |
金属工艺 | 226篇 |
机械仪表 | 227篇 |
建筑科学 | 285篇 |
矿业工程 | 51篇 |
能源动力 | 361篇 |
轻工业 | 880篇 |
水利工程 | 31篇 |
石油天然气 | 55篇 |
武器工业 | 2篇 |
无线电 | 613篇 |
一般工业技术 | 976篇 |
冶金工业 | 386篇 |
原子能技术 | 58篇 |
自动化技术 | 889篇 |
出版年
2024年 | 32篇 |
2023年 | 78篇 |
2022年 | 106篇 |
2021年 | 212篇 |
2020年 | 205篇 |
2019年 | 192篇 |
2018年 | 285篇 |
2017年 | 237篇 |
2016年 | 285篇 |
2015年 | 198篇 |
2014年 | 271篇 |
2013年 | 791篇 |
2012年 | 280篇 |
2011年 | 302篇 |
2010年 | 289篇 |
2009年 | 337篇 |
2008年 | 232篇 |
2007年 | 197篇 |
2006年 | 169篇 |
2005年 | 100篇 |
2004年 | 116篇 |
2003年 | 130篇 |
2002年 | 182篇 |
2001年 | 200篇 |
2000年 | 139篇 |
1999年 | 129篇 |
1998年 | 208篇 |
1997年 | 148篇 |
1996年 | 74篇 |
1995年 | 36篇 |
1994年 | 39篇 |
1993年 | 25篇 |
1992年 | 17篇 |
1991年 | 20篇 |
1990年 | 17篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 10篇 |
1986年 | 10篇 |
1985年 | 18篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 9篇 |
1981年 | 11篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1978年 | 12篇 |
1976年 | 8篇 |
1973年 | 6篇 |
1965年 | 4篇 |
排序方式: 共有6463条查询结果,搜索用时 15 毫秒
91.
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
92.
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
93.
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
94.
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
95.
96.
E. BORIE G. GANTENBEIN B. JÖDICKE G. DAMMERTZ O. DUMBRAJS T. GEIST 《International Journal of Electronics》2013,100(5-6):687-720
The gyrotron is a powerful source of millimetre wave radiation. Fusion applications require more power per tube than is currently available This in turn means that the resonator must be highly overmoded, with a dense mode spectrum, which leads to mode competition. The influence of external parameters, such as the applied magnetic field, electron beam, and resonator geometry, on mode competition in tubes designed to operate at 150 and 140 GHz in the TE03 mode is investigated theoretically and experimentally. It can be shown that even when the mode spectrum is fairly dense, single mode operation of a gyrotron is possible. The influence of startup conditions on output power is investigated in the 150 GHz experiment. In some cases, modes with an axial index of 2 were excited. 相似文献
97.
98.
东营凹陷和惠民凹陷作为济阳坳陷南部两个相邻的、构造格局相似的陆相箕状断陷,其石油地质特征有相似之处,但油气富集程度有明显差异。控制油气富集的主要因素有油源条件、构造特征、火山活动以及生储盖组合与构造的配置等。生储盖组合与构造特征的配置,是造成不同构造部位主要储油气层位和油气藏类型差异性的直接原因。结合油源特征、生储盖组合和输导系统特征,东营、惠民凹陷的油气成藏模式可归为5种类型:洼陷带自生自储-侧向运移成藏模式、洼陷区上生下储-垂向运移成藏模式、中央隆起带和北部陡坡带下生上储-垂向运移成藏模式、南部斜坡带下生上储-复合运移成藏模式和周边凸起区新生古储-复合成藏模式。 相似文献
99.
This paper presents the most suitable image processing techniques being used at present for recognising features either lying on the seafloor or floating in the water column. The preprocessing methodology is already incorporated in the sonar system, and as we cannot access the raw data, it is not included in this paper. The studied images correspond to the Cabrera Archipelago, in the Mediterranean Sea. 相似文献
100.
A new procedure is presented for the synthesis of diagonal compensators for N × N linear multivariable systems that are free of fixed modes with respect to constant diagonal output feedbacks. The synthesis procedure employs simple polynomial algebra and it is in the form of an N-step algorithm. The geometric configurations 2N- and 2N-cells in N-space are shown to be especially suitable for visualizing diagonal feedback and aiding the application of the synthesis algorithm. 相似文献