全文获取类型
收费全文 | 2602篇 |
免费 | 103篇 |
国内免费 | 5篇 |
学科分类
工业技术 | 2710篇 |
出版年
2023年 | 25篇 |
2022年 | 27篇 |
2021年 | 70篇 |
2020年 | 40篇 |
2019年 | 50篇 |
2018年 | 56篇 |
2017年 | 63篇 |
2016年 | 53篇 |
2015年 | 61篇 |
2014年 | 84篇 |
2013年 | 169篇 |
2012年 | 134篇 |
2011年 | 141篇 |
2010年 | 101篇 |
2009年 | 92篇 |
2008年 | 131篇 |
2007年 | 103篇 |
2006年 | 96篇 |
2005年 | 96篇 |
2004年 | 71篇 |
2003年 | 71篇 |
2002年 | 74篇 |
2001年 | 50篇 |
2000年 | 33篇 |
1999年 | 51篇 |
1998年 | 122篇 |
1997年 | 83篇 |
1996年 | 73篇 |
1995年 | 31篇 |
1994年 | 49篇 |
1993年 | 34篇 |
1992年 | 22篇 |
1991年 | 16篇 |
1990年 | 23篇 |
1989年 | 30篇 |
1988年 | 16篇 |
1987年 | 14篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 20篇 |
1983年 | 19篇 |
1982年 | 13篇 |
1980年 | 17篇 |
1979年 | 15篇 |
1977年 | 16篇 |
1976年 | 19篇 |
1975年 | 9篇 |
1974年 | 10篇 |
1972年 | 8篇 |
1969年 | 11篇 |
排序方式: 共有2710条查询结果,搜索用时 15 毫秒
61.
62.
63.
Agents’ model of uncertainty 总被引:4,自引:4,他引:0
Multi-agent systems play an increasing role in sensor networks, software engineering, web design, e-commerce, robotics, and
many others areas. Uncertainty is a fundamental property of these areas. Agent-based systems use probabilistic and other uncertainty
models developed earlier without explicit consideration of agents. This paper explores the impact of agents on uncertainty
models and theories. We compare two methods of introducing agents to uncertainty theories and propose a new theory called
the agent-based uncertainty theory (AUT). We show advantages of AUT for advancing multi-agent systems and for solving an internal
fundamental question of uncertainty theories, that is identifying coherent approaches to uncertainty. The advantages of AUT
are that it provides a uniform agent-based representation and an operational empirical interpretation for several uncertainty
theories such as rough set theory, fuzzy sets theory, evidence theory, and probability theory. We show also that the introduction
of agents to intuitionist uncertainty formalisms can reduce their conceptual complexity. To build such uniformity the AUT
exploits the fact that agents as independent entities can give conflicting evaluations of the same attribute. The AUT is based
on complex aggregations of crisp (non-fuzzy) conflicting judgments of agents. The generality of AUT is derived from the logical
classification of types (orders) of conflicts in the agent populations. At the first order of conflict, the two agent populations
are disjoint and there is no interference of logic values assigned to any statement p and its negation by agents. The second order of conflict models superposition (interference) of logic values for overlapping
agent populations where an agent assigns conflicting logic values (true, false) to the same attribute simultaneously.
相似文献
Boris KovalerchukEmail: |
64.
Jacques-Olivier Lachaud Boris Thibert 《Journal of Mathematical Imaging and Vision》2016,54(2):162-180
This paper presents new topological and geometric properties of Gauss digitizations of Euclidean shapes, most of them holding in arbitrary dimension d. We focus on r-regular shapes sampled by Gauss digitization at gridstep h. The digitized boundary is shown to be close to the Euclidean boundary in the Hausdorff sense, the minimum distance \(\frac{\sqrt{d}}{2}h\) being achieved by the projection map \(\xi \) induced by the Euclidean distance. Although it is known that Gauss digitized boundaries may not be manifold when \(d \ge 3\), we show that non-manifoldness may only occur in places where the normal vector is almost aligned with some digitization axis, and the limit angle decreases with h. We then have a closer look at the projection of the digitized boundary onto the continuous boundary by \(\xi \). We show that the size of its non-injective part tends to zero with h. This leads us to study the classical digital surface integration scheme, which allocates a measure to each surface element that is proportional to the cosine of the angle between an estimated normal vector and the trivial surface element normal vector. We show that digital integration is convergent whenever the normal estimator is multigrid convergent, and we explicit the convergence speed. Since convergent estimators are now available in the literature, digital integration provides a convergent measure for digitized objects. 相似文献
65.
Michal Mereš Ivan Melo Boris Tomášik Vladimír Balek Vladimír ?erný 《Computer Physics Communications》2011,182(12):2561-2566
We propose a novel algorithm, called REGGAE, for the generation of momenta of a given sample of particle masses, evenly distributed in Lorentz-invariant phase space and obeying energy and momentum conservation. In comparison to other existing algorithms, REGGAE is designed for the use in multiparticle production in hadronic and nuclear collisions where many hadrons are produced and a large part of the available energy is stored in the form of their masses. The algorithm uses a loop simulating multiple collisions which lead to production of configurations with reasonably large weights.
Program summary
Program title: REGGAE (REscattering-after-Genbod GenerAtor of Events)Catalogue identifier: AEJR_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJR_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 1523No. of bytes in distributed program, including test data, etc.: 9608Distribution format: tar.gzProgramming language: C++Computer: PC Pentium 4, though no particular tuning for this machine was performed.Operating system: Originally designed on Linux PC with g++, but it has been compiled and ran successfully on OS X with g++ and MS Windows with Microsoft Visual C++ 2008 Express Edition, as well.RAM: This depends on the number of particles which are generated. For 10 particles like in the attached example it requires about 120 kB.Classification: 11.2Nature of problem: The task is to generate momenta of a sample of particles with given masses which obey energy and momentum conservation. Generated samples should be evenly distributed in the available Lorentz-invariant phase space.Solution method: In general, the algorithm works in two steps. First, all momenta are generated with the GENBOD algorithm. There, particle production is modeled as a sequence of two-body decays of heavy resonances. After all momenta are generated this way, they are reshuffled. Each particle undergoes a collision with some other partner such that in the pair center of mass system the new directions of momenta are distributed isotropically. After each particle collides only a few times, the momenta are distributed evenly across the whole available phase space. Starting with GENBOD is not essential for the procedure but it improves the performance.Running time: This depends on the number of particles and number of events one wants to generate. On a LINUX PC with 2 GHz processor, generation of 1000 events with 10 particles each takes about 3 s. 相似文献66.
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
67.
Joanna J.J. Wang Jennifer S.K. ChanS.T. Boris Choy 《Computational statistics & data analysis》2011,55(1):852-862
This paper studies a heavy-tailed stochastic volatility (SV) model with leverage effect, where a bivariate Student-t distribution is used to model the error innovations of the return and volatility equations. Choy et al. (2008) studied this model by expressing the bivariate Student-t distribution as a scale mixture of bivariate normal distributions. We propose an alternative formulation by first deriving a conditional Student-t distribution for the return and a marginal Student-t distribution for the log-volatility and then express these two Student-t distributions as a scale mixture of normal (SMN) distributions. Our approach separates the sources of outliers and allows for distinguishing between outliers generated by the return process or by the volatility process, and hence is an improvement over the approach of Choy et al. (2008). In addition, it allows an efficient model implementation using the WinBUGS software. A simulation study is conducted to assess the performance of the proposed approach and its comparison with the approach by Choy et al. (2008). In the empirical study, daily exchange rate returns of the Australian dollar to various currencies and daily stock market index returns of various international stock markets are analysed. Model comparison relies on the Deviance Information Criterion and convergence diagnostic is monitored by Geweke’s convergence test. 相似文献
68.
T. Huber 《Computer Physics Communications》2006,175(2):122-144
We present the Mathematica package HypExp which allows to expand hypergeometric functions around integer parameters to arbitrary order. At this, we apply two methods, the first one being based on an integral representation, the second one on the nested sums approach. The expansion works for both symbolic argument z and unit argument. We also implemented new classes of integrals that appear in the first method and that are, in part, yet unknown to Mathematica.
Program summary
Title of program:HypExpCatalogue identifier:ADXF_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXF_v1_0Program obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandLicence:noneComputers:Computers running Mathematica under Linux or WindowsOperating system:Linux, WindowsProgram language:MathematicaNo. of bytes in distributed program, including test data, etc.:739 410No. of lines in distributed program, including test data, etc.:89 747Distribution format:tar.gzOther package needed:the package HPL, included in the distributionExternal file required:noneNature of the physical problem:Expansion of hypergeometric functions around integer-valued parameters. These are needed in the context of dimensional regularization for loop and phase space integrals.Method of solution:Algebraic manipulation of nested sums and integral representation.Restrictions on complexity of the problem:Limited by the memory availableTypical running time:Strongly depending on the problem and the availability of libraries. 相似文献69.
We report the results of electron paramagnetic resonance studies of GdX (X=As, Sb, Bi, S, Se). The temperature dependence of the linewidth H and effective g-factorg
eff are discussed. Values for the Néel temperatureT
N are inferred from coincident anomalies in H andg
eff. In the cases of X=S and Se, our estimates ofT
N are significantly lower than theT
N inferred from static susceptibility measurements. A possible source of the discrepancy is discussed.Supported by the National Science Foundation Grant No. DMR-74-08033.Work performed under the auspices of the U.S. ERDA.Supported by the National Science Foundation. 相似文献
70.
Adalberto Llarena Jesus Savage Angel Kuri Boris Escalante-Ramírez 《Journal of Intelligent and Robotic Systems》2012,66(1-2):75-109
This paper proposes an approach that solves the Robot Localization problem by using a conditional state-transition Hidden Markov Model (HMM). Through the use of Self Organized Maps (SOMs) a Tolerant Observation Model (TOM) is built, while odometer-dependent transition probabilities are used for building an Odometer-Dependent Motion Model (ODMM). By using the Viterbi Algorithm and establishing a trigger value when evaluating the state-transition updates, the presented approach can easily take care of Position Tracking (PT), Global Localization (GL) and Robot Kidnapping (RK) with an ease of implementation difficult to achieve in most of the state-of-the-art localization algorithms. Also, an optimization is presented to allow the algorithm to run in standard microprocessors in real time, without the need of huge probability gridmaps. 相似文献