全文获取类型
收费全文 | 3115篇 |
免费 | 199篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 22篇 |
综合类 | 4篇 |
化学工业 | 746篇 |
金属工艺 | 28篇 |
机械仪表 | 55篇 |
建筑科学 | 122篇 |
矿业工程 | 10篇 |
能源动力 | 129篇 |
轻工业 | 521篇 |
水利工程 | 35篇 |
石油天然气 | 8篇 |
无线电 | 275篇 |
一般工业技术 | 450篇 |
冶金工业 | 79篇 |
原子能技术 | 34篇 |
自动化技术 | 798篇 |
出版年
2024年 | 1篇 |
2023年 | 29篇 |
2022年 | 38篇 |
2021年 | 156篇 |
2020年 | 88篇 |
2019年 | 106篇 |
2018年 | 117篇 |
2017年 | 120篇 |
2016年 | 151篇 |
2015年 | 103篇 |
2014年 | 192篇 |
2013年 | 274篇 |
2012年 | 262篇 |
2011年 | 259篇 |
2010年 | 199篇 |
2009年 | 202篇 |
2008年 | 181篇 |
2007年 | 165篇 |
2006年 | 95篇 |
2005年 | 92篇 |
2004年 | 71篇 |
2003年 | 80篇 |
2002年 | 57篇 |
2001年 | 27篇 |
2000年 | 26篇 |
1999年 | 34篇 |
1998年 | 30篇 |
1997年 | 23篇 |
1996年 | 27篇 |
1995年 | 21篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1978年 | 4篇 |
排序方式: 共有3316条查询结果,搜索用时 15 毫秒
61.
Javier Prez-Ramírez 《Applied catalysis. B, Environmental》2007,70(1-4):31-35
European authorities consider that N2O emissions from nitric acid plants can be reduced to a large extent at a relatively low cost. Two regulation approaches can have major implications for the fertilizer industry in Europe. The EU integrated pollution prevention and control (IPPC) directive will be effective from October 2007 for existing plants. In this, emission permits will be based on best available techniques (BAT). Additionally, the EU commission will shortly consider whether the emission trading directive should be applicable to cover other greenhouse gases besides CO2. This paper discusses advantages and drawbacks of these approaches, with emphasis on how emission trading with N2O can be turned into a win–win situation both for European governments and for the fertilizer industry. 相似文献
62.
Javier Arellano-Verdejo Enrique Alba Salvador Godoy-Calderon 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2016,20(3):895-905
Clustering algorithms, a fundamental base for data mining procedures and learning techniques, suffer from the lack of efficient methods for determining the optimal number of clusters to be found in an arbitrary dataset. The few methods existing in the literature always use some sort of evolutionary algorithm having a cluster validation index as its objective function. In this article, a new evolutionary algorithm, based on a hybrid model of global and local heuristic search, is proposed for the same task, and some experimentation is done with different datasets and indexes. Due to its design, independent of any clustering procedure, it is applicable to virtually any clustering method like the widely used \(k\)-means algorithm. Moreover, the use of non-parametric statistical tests over the experimental results, clearly show the proposed algorithm to be more efficient than other evolutionary algorithms currently used for the same task. 相似文献
63.
64.
Beatriz Pariente-Martinez Martin Gonzalez-Rodriguez Daniel Fernandez-Lanvin Javier De Andres-Suarez 《Universal Access in the Information Society》2016,15(2):237-247
The influence of aging on computer interaction has been widely analyzed in human–computer interaction research literature. Despite this, there are no age-based user maps that could support the user-interface customization. Studying the specific needs and constraints of these groups is crucial in order to adapt a user interface to the user’s interaction requirements. This work studies the performance of a sample of participants on three different basic tasks (pointing, dragging and dropping, and text selection) and the influence of age for each of them. It is concluded that this influence differs between specific activities. A group profile map that can support automatic classification in the future has been obtained. 相似文献
65.
4:1! Google’s artificial intelligence (AI) program, AlphaGo, has won Go Master Lee Sedol in a best-of-five competition held in Korean March 9?15, 2016. Seen by many as a landmark moment for AI, the outcome did not come as a surprise, considering the excellent combination of 1920 CPUs with sophisticated AI algorithms, including neural networks and Monte Carlo tree search (Gibney, 2016; Silver et al., 2016). Indeed, research on distributed computing and artificial intelligence (DCAI) has matured during the last decade and many effective applications are now deployed, performing an increasingly important role in modern computer science, including the two most hyped technologies: Internet of Things and Big Data. Indeed, it is fair to say that the application of artificial intelligence in distributed environments is becoming an essential element of high added value and economic potential. 相似文献
66.
Xavier Suau Javier Ruiz-Hidalgo Josep R. Casas 《Computer Vision and Image Understanding》2013,117(3):281-288
End-effectors are usually related to the location of limbs, and their reliable detection enables robust body tracking as well as accurate pose estimation. Recent innovation in depth cameras has re-stated the pose estimation problem. We focus on the information provided by these sensors, for which we borrow the name 2.5D data from the Graphics community. In this paper we propose a human pose estimation algorithm based on topological propagation. Geometric Deformable Models are used to carry out such propagation, implemented according to the Narrow Band Level Set approach. A variant of the latter method is proposed, including a density restriction which helps preserving the topological properties of the object under analysis. Principal end-effectors are extracted from a directed graph weighted with geodesic distances, also providing a skeletal-like structure describing human pose. An evaluation against reference methods is performed with promising results. The proposed solution allows a frame-wise end-effector detection, with no temporal tracking involved, which may be generalized to the tracking of other objects beyond human body. 相似文献
67.
Recent vehicular routing proposals use real-time road traffic density estimates to dynamically select forwarding paths. Estimating the traffic density in vehicular ad hoc networks requires the transmission of additional dedicated messages increasing the communications load. These proposals are generally based on unicast sender-based forwarding schemes. The greedy nature of sender-based forwarding can result in the selection of forwarders with weak radio links that might compromise the end-to-end performance. To overcome these limitations, this paper presents TOPOCBF, a novel contention-based broadcast forwarding protocol that dynamically selects forwarding paths based on their capability to route packets between anchor points. Such capability is estimated by means of a multi-hop connectivity metric. The obtained results demonstrate that TOPOCBF can provide good packet delivery ratios while reducing the communications load compared to unicast sender-based forwarding schemes using road traffic density estimates. 相似文献
68.
Manuela Ruiz-Montiel Javier Boned Juan Gavilanes Eduardo Jiménez Lawrence Mandow José-Luis Pérez-de-la-Cruz 《Advanced Engineering Informatics》2013,27(2):230-245
Shape grammars are a powerful and appealing formalism for automatic shape generation in computer-based design systems. This paper presents a proposal complementing the generative power of shape grammars with reinforcement learning techniques. We use simple (naive) shape grammars capable of generating a large variety of different designs. In order to generate those designs that comply with given design requirements, the grammar is subject to a process of machine learning using reinforcement learning techniques. Based on this method, we have developed a system for architectural design, aimed at generating two-dimensional layout schemes of single-family housing units. Using relatively simple grammar rules, we learn to generate schemes that satisfy a set of requirements stated in a design guideline. Obtained results are presented and discussed. 相似文献
69.
The Economic Impact of Water Evaporation Losses from Water Reservoirs in the Segura Basin,SE Spain 总被引:1,自引:0,他引:1
David Martínez-Granados José Francisco Maestre-Valero Javier Calatrava Victoriano Martínez-Alvarez 《Water Resources Management》2011,25(13):3153-3175
In this paper we assess the economic impact of evaporation losses from great dams (GDs) and on-farm agricultural water reservoirs
(AWRs) in the semi-arid Segura River basin, SE Spain. Evaporation losses from water reservoirs reduce the high water use efficiency
reached in agriculture by means of other techniques such as well-built water pipes or drip irrigation and have a substantial
economic impact. Evaporation losses have been calculated using Class-A pan evaporation data and pan coefficients, whereas
their economic impact has been assessed using an economic mathematical programming model that simulates land and water allocation
in the different irrigated areas of the basin. Our results show that annual evaporation from GDs and AWRs represents 8.7%
of the water currently available for irrigation in the Segura basin. The economic impact of such losses has been estimated
in a reduction of 6.3% of the value of agricultural production and 5.4% of the farm net margin. As less water is effectively
available for farmers the basin’s irrigated area is reduced in a 7.5%. This impact is greater, in both absolute and relative
terms, in the areas accommodating the most intensive and profitable irrigated agriculture. The applied methodology and results
could be useful to regional water agencies and collective irrigation schemes for future planning and management, including
the assessment of alternatives for reducing evaporation from reservoirs. 相似文献
70.
Basil Mohammed Al-Hadithi Antonio Javier Barragán José Manuel Andújar Agustín Jiménez 《Applied Soft Computing》2013,13(12):4802-4812
In this paper, a fuzzy based Variable Structure Control (VSC) with guaranteed stability is presented. The main objective is to obtain an improved performance of highly non-linear unstable systems. The main contribution of this work is that, firstly, new functions for chattering reduction and error convergence without sacrificing invariant properties are proposed, which is considered the main drawback of the VSC control. Secondly, the global stability of the controlled system is guaranteed.The well known weighting parameters approach, is used in this paper to optimize local and global approximation and modeling capability of T-S fuzzy model.A one link robot is chosen as a nonlinear unstable system to evaluate the robustness, effectiveness and remarkable performance of optimization approach and the high accuracy obtained in approximating nonlinear systems in comparison with the original T-S model. Simulation results indicate the potential and generality of the algorithm. The application of the proposed FLC-VSC shows that both alleviation of chattering and robust performance are achieved with the proposed FLC-VSC controller. The effectiveness of the proposed controller is proven infront of disturbances and noise effects. 相似文献