全文获取类型
收费全文 | 5643篇 |
免费 | 220篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 140篇 |
综合类 | 13篇 |
化学工业 | 1448篇 |
金属工艺 | 123篇 |
机械仪表 | 104篇 |
建筑科学 | 432篇 |
矿业工程 | 10篇 |
能源动力 | 127篇 |
轻工业 | 755篇 |
水利工程 | 36篇 |
石油天然气 | 13篇 |
无线电 | 292篇 |
一般工业技术 | 933篇 |
冶金工业 | 663篇 |
原子能技术 | 58篇 |
自动化技术 | 723篇 |
出版年
2022年 | 44篇 |
2021年 | 71篇 |
2020年 | 55篇 |
2019年 | 59篇 |
2018年 | 69篇 |
2017年 | 88篇 |
2016年 | 117篇 |
2015年 | 137篇 |
2014年 | 154篇 |
2013年 | 252篇 |
2012年 | 230篇 |
2011年 | 246篇 |
2010年 | 211篇 |
2009年 | 231篇 |
2008年 | 218篇 |
2007年 | 252篇 |
2006年 | 204篇 |
2005年 | 204篇 |
2004年 | 188篇 |
2003年 | 130篇 |
2002年 | 138篇 |
2001年 | 115篇 |
2000年 | 99篇 |
1999年 | 78篇 |
1998年 | 89篇 |
1997年 | 91篇 |
1996年 | 85篇 |
1995年 | 77篇 |
1994年 | 59篇 |
1993年 | 79篇 |
1992年 | 80篇 |
1991年 | 53篇 |
1990年 | 62篇 |
1989年 | 61篇 |
1987年 | 71篇 |
1986年 | 58篇 |
1985年 | 73篇 |
1984年 | 65篇 |
1983年 | 61篇 |
1982年 | 64篇 |
1981年 | 69篇 |
1980年 | 68篇 |
1979年 | 69篇 |
1978年 | 53篇 |
1977年 | 55篇 |
1976年 | 59篇 |
1975年 | 58篇 |
1974年 | 67篇 |
1973年 | 50篇 |
1970年 | 41篇 |
排序方式: 共有5870条查询结果,搜索用时 15 毫秒
81.
Daniel E. Rivera Hyunjin Lee Hans D. Mittelmann Martin W. Braun 《Journal of Process Control》2009,19(4):623-635
This paper considers the use of constrained minimum crest factor multisine signals as inputs for plant-friendly identification testing of chemical process systems. The methodology presented here effectively integrates operating restrictions, information-theoretic requirements, and state-of-the-art optimization techniques to design minimum crest factor multisine signals meeting important user-specified time and frequency domain properties. A series of optimization problem formulations relevant to problems in linear, nonlinear, and multivariable system identification are presented; these culminate with their application to the modeling of the Weischedel–McAvoy high-purity distillation column problem, a demanding nonlinear and highly interactive system. The effectiveness of these signals for modeling for control purposes and the ability to incorporate a priori nonlinear models in the signal design procedure are demonstrated in this distillation system case study. 相似文献
82.
A Parallelization Approach for Hard Real-Time Systems and Its Application on Two Industrial Programs
Martin?FriebEmail author Ralf?Jahr Haluk?Ozaktas Andreas?Hugl Hans?Regler Theo?Ungerer 《International journal of parallel programming》2016,44(6):1296-1336
Applications in industry often have grown and improved over many years. Since their performance demands increase, they also need to benefit from the availability of multi-core processors. However, a reimplementation from scratch and even a restructuring of these industrial applications is very expensive, often due to high certification efforts. Therefore, a strategy for a systematic parallelization of legacy code is needed. We present a parallelization approach for hard real-time systems, which ensures a high reusage of legacy code and preserves timing analysability. To show its applicability, we apply it on the core algorithm of an avionics application as well as on the control program of a large construction machine. We create models of the legacy programs showing the potential of parallelism, optimize them and change the source codes accordingly. The parallelized applications are placed on a predictable multi-core processor with up to 18 cores. For evaluation, we compare the worst case execution times and their speedups. Furthermore, we analyse limitations coming up at the parallelization process. 相似文献
83.
Democratizing Journalism – How User‐Generated Content and User Communities Affect Publishers’ Business Models 下载免费PDF全文
Publishers, today, are struggling with their business model: Their efforts to convert traditional content into digital products seem to be insufficient as recipients expect more than simply the mere digitalization of content. Dissatisfied with solely being informed by selected journalists, modern recipients are often interested in acquiring information from various sources, in discussing with others, or even in contributing with their own content. Hence, recipients seem to evolve from being simply readers to contributors themselves. With regard to the established term ‘user‐generated content’, we refer to those co‐creating recipients as users. To underline these assumptions, the present study explores (1) users’ expectations of sources of content and (2) their willingness to provide their own content. Our findings show that both user‐generated content and professional journalists’ content is of value to users. Second, we show that users are mainly driven to contribute by their own expertise, welfare of others, and personal acceptance in the community. With this study, we consider mainly the changed user behaviour in order to derive implications of user involvement for future business models of publishers, in particular on the customer value proposition as well as key resources and key processes. 相似文献
84.
Bram?KlievinkEmail authorView authors OrcID profile Bart-Jan?Romijn Scott?Cunningham Hans?de?Bruijn 《Information Systems Frontiers》2017,19(2):267-283
Big data is being implemented with success in the private sector and science. Yet the public sector seems to be falling behind, despite the potential value of big data for government. Government organizations do recognize the opportunities of big data but seem uncertain about whether they are ready for the introduction of big data, and if they are adequately equipped to use big data. This paper addresses those uncertainties. It presents an assessment framework for evaluating public organizations’ big data readiness. Doing so demystifies the concept of big data, as it is expressed in terms of specific and measureable organizational characteristics. The framework was tested by applying it to organizations in the Dutch public sector. The results suggest that organizations may be technically capable of using big data, but they will not significantly gain from these activities if the applications do not fit their organizations and main statutory tasks. The framework proved helpful in pointing out areas where public sector organizations could improve, providing guidance on how government can become more big data ready in the future. 相似文献
85.
In this paper, we present an automatic C-code generation strategy for real-time nonlinear model predictive control (NMPC), which is designed for applications with kilohertz sample rates. The corresponding code export module has been implemented within the software package ACADO Toolkit. It is capable of exporting fixed step-size integrators together with their sensitivities as well as a real-time Gauss–Newton method. Here, we employ the symbolic representation of optimal control problems in ACADO in order to auto-generate plain C-code which is optimized for final production. The exported code has been tested for model predictive control scenarios comprising constrained nonlinear dynamic systems with four states and a control horizon of ten samples. The numerical simulations show a promising performance of the exported code being able to provide feedback in much less than a millisecond. 相似文献
86.
87.
A survey on industrial applications of fuzzy control 总被引:4,自引:0,他引:4
Fuzzy control has long been applied to industry with several important theoretical results and successful results. Originally introduced as model-free control design approach, model-based fuzzy control has gained widespread significance in the past decade. This paper presents a survey on recent developments of analysis and design of fuzzy control systems focused on industrial applications reported after 2000. 相似文献
88.
In this paper we revisit the computation and visualization of equivalents to isocontours in uncertain scalar fields. We model uncertainty by discrete random fields and, in contrast to previous methods, also take arbitrary spatial correlations into account. Starting with joint distributions of the random variables associated to the sample locations, we compute level crossing probabilities for cells of the sample grid. This corresponds to computing the probabilities that the well‐known symmetry‐reduced marching cubes cases occur in random field realizations. For Gaussian random fields, only marginal density functions that correspond to the vertices of the considered cell need to be integrated. We compute the integrals for each cell in the sample grid using a Monte Carlo method. The probabilistic ansatz does not suffer from degenerate cases that usually require case distinctions and solutions of ill‐conditioned problems. Applications in 2D and 3D, both to synthetic and real data from ensemble simulations in climate research, illustrate the influence of spatial correlations on the spatial distribution of uncertain isocontours. 相似文献
89.
Huth J Buchholz M Kraus JM Mølhave K Gradinaru C v Wichert G Gress TM Neumann H Kestler HA 《Computer methods and programs in biomedicine》2011,104(2):227-234
The direct observation of cells over time using time-lapse microscopy can provide deep insights into many important biological processes. Reliable analyses of motility, proliferation, invasive potential or mortality of cells are essential to many studies involving live cell imaging and can aid in biomarker discovery and diagnostic decisions. Given the vast amount of image- and time-series data produced by modern microscopes, automated analysis is a key feature to capitalize the potential of time-lapse imaging devices. To provide fast and reproducible analyses of multiple aspects of cell behaviour, we developed TimeLapseAnalyzer. Apart from general purpose image enhancements and segmentation procedures, this extensible, self-contained, modular cross-platform package provides dedicated modalities for fast and reliable analysis of multi-target cell tracking, scratch wound healing analysis, cell counting and tube formation analysis in high throughput screening of live-cell experiments. TimeLapseAnalyzer is freely available (MATLAB, Open Source) at http://www.informatik.uni-ulm.de/ni/mitarbeiter/HKestler/tla. 相似文献
90.
Controlling the dynamics of a constrained manipulator includesposition tracking as well as stabilization of the contact wrench.In this paper we derive a control scheme, that makes it possible to treat position and force control independently.The approach is based on a mass-orthogonal splitting of the space of joint torques, allowing independent actuation and therefore independent specification of control laws. An appropriate definition of the reference wrenchmakes it possible to achieve independent stability of the position and force loop. 相似文献