全文获取类型
收费全文 | 2869篇 |
免费 | 238篇 |
国内免费 | 161篇 |
专业分类
电工技术 | 65篇 |
综合类 | 298篇 |
化学工业 | 75篇 |
金属工艺 | 45篇 |
机械仪表 | 76篇 |
建筑科学 | 164篇 |
矿业工程 | 20篇 |
能源动力 | 21篇 |
轻工业 | 63篇 |
水利工程 | 58篇 |
石油天然气 | 34篇 |
武器工业 | 5篇 |
无线电 | 97篇 |
一般工业技术 | 409篇 |
冶金工业 | 1009篇 |
原子能技术 | 12篇 |
自动化技术 | 817篇 |
出版年
2024年 | 10篇 |
2023年 | 48篇 |
2022年 | 77篇 |
2021年 | 103篇 |
2020年 | 79篇 |
2019年 | 84篇 |
2018年 | 83篇 |
2017年 | 66篇 |
2016年 | 81篇 |
2015年 | 77篇 |
2014年 | 129篇 |
2013年 | 135篇 |
2012年 | 141篇 |
2011年 | 235篇 |
2010年 | 183篇 |
2009年 | 205篇 |
2008年 | 221篇 |
2007年 | 220篇 |
2006年 | 217篇 |
2005年 | 164篇 |
2004年 | 121篇 |
2003年 | 119篇 |
2002年 | 98篇 |
2001年 | 76篇 |
2000年 | 45篇 |
1999年 | 33篇 |
1998年 | 18篇 |
1997年 | 27篇 |
1996年 | 21篇 |
1995年 | 20篇 |
1994年 | 25篇 |
1993年 | 12篇 |
1992年 | 15篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 9篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1964年 | 3篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1958年 | 2篇 |
1957年 | 4篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有3268条查询结果,搜索用时 15 毫秒
41.
ANNETTE KARMILOFF-SMITH 《连接科学》1992,4(3-4):253-269
In this article I discuss the nature/nurture debate in terms of evidence and theorizing from the field of cognitive development, and pinpoint various problems where the Connectionist framework needs to be further explored from this perspective. Evidence from normal and abnormal developmental phenotypes points to some domain-specific constraints on early learning. Yet, by invoking the dynamics of epigenesis, I avoid recourse to a strong Nativist stance and remain within the general spirit of Connectionism. 相似文献
42.
注塑流动与传热分析的自适应隐式控制体积法 总被引:1,自引:1,他引:1
在注塑流动与传热分析中采用自适应隐式控制体积法,利用自动控制的参数识别方法来自动调节时间步长,在每个时间步长流动将向前推进大约半个单元大小的距离,厚度方向的温度采用契比雪夫配点法进行计算,压力方程的求解方法是预条件共轭梯度法。计算结果表明,自适应隐式控制体积法的时间复杂度是结点数目的平方,而且1h之内可以求解10000结点规模的问题。 相似文献
43.
With a combined compact difference scheme for the spatial discretization and the Crank–Nicolson scheme for the temporal discretization, respectively, a high-order alternating direction implicit method (ADI) is proposed for solving unsteady two dimensional convection–diffusion equations. The method is sixth-order accurate in space and second-order accurate in time. The resulting matrix at each ADI computation step corresponds to a triple-tridiagonal system which can be effectively solved with a considerable saving in computing time. In practice, Richardson extrapolation is exploited to increase the temporal accuracy. The unconditional stability is proved by means of Fourier analysis for two dimensional convection–diffusion problems with periodic boundary conditions. Numerical experiments are conducted to demonstrate the efficiency of the proposed method. Moreover, the present method preserves the higher order accuracy for convection-dominated problems. 相似文献
44.
Computational Problem Solving in Spatial Substrates -- A Cognitive Systems Engineering Approach
下载免费PDF全文
![点击此处可从《International Journal of Software and Informatics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Christian Freksa 《International Journal of Software and Informatics》2015,9(2):279-288
The ability to perform spatial tasks is crucial for everyday life and of great importance to cognitive agents such as humans, animals, and autonomous robots. A common artificial intelligence approach to accomplish spatial tasks is to represent spatial configurations and tasks in form of detailed knowledge about various aspects of space and
time. Suitable algorithms then use the representations to compute solutions to spatial problems. In comparison, natural embodied and situated agents often solve spatial tasks without detailed knowledge about geometric, topological, or mechanical laws; they directly relate actions to effects that are due to spatio-temporal affordances in their bodies and environments. Accordingly, we propose a paradigm that makes the spatio-temporal
substrate an integral part of the engine that drives spatial problem solving. We argue that spatial and temporal structures in body and environment can substantially support (and even replace) reasoning effort in computational processes: physical manipulation and perception in spatial environments substitute formal computation. While the approach is well known – for example, we employ diagrams as spatial substrate for geometric problem solving and maps for wayfinding – the underlying principle has not been systematically investigated or formally analyzed as a paradigm of cognitive processing. Topology, distance, and orientation constraints are all integrated and interdependent in truly 2- or 3-dimensional space. Exploiting this fact may not only help overcome the need for acquiring detailed knowledge about the interrelationships between different aspects of space; it also can point to a way of avoiding exploding computational complexity that occurs when we deal with these aspects of space in complex real-world scenarios. Our approach employs affordance-based object-level problem solving to complement knowledge-level formal approaches. We will assess strengths and weaknesses of the new cognitive systems paradigm. 相似文献
45.
对常用的回归方法进行研究.此类方法虽然几何解释明确、易于求解,但均须事先确定(或假定)变量间的因果关系,再考虑建模,在实际应用中,对于很难确定变量的因果关系的问题,如物联网数据分析,上述方法就会失效.为此,提出一种无需假定因变量的隐目标回归方法.该方法易于核化,可以推广到非线性回归问题.通过人工数据和国际标准数据集上的实验验证了所提算法的有效性. 相似文献
46.
基于ELADI算法的平面二维水环境模型WESC2D,定量研究大辽河潮区界与潮流界的时空变化规律。在模拟和验证大辽河潮位变化过程基础上,通过数值试验系统地模拟分析了上游径流量及汇流比、下游潮差和海平面上升对大辽河潮区界与潮流界的影响规律,并以1999年—2009年水文过程为条件定量研究大辽河潮流界的年、月变化及潮流界位置出现频率。结果表明,径流是影响大辽河潮区界与潮流界位置的主要因素,大辽河潮流界远远超过三岔河。 相似文献
47.
Julius Parulek Daniel Jönsson Timo Ropinski Stefan Bruckner Anders Ynnerman Ivan Viola 《Computer Graphics Forum》2014,33(6):276-287
Molecular visualization is often challenged with rendering of large molecular structures in real time. We introduce a novel approach that enables us to show even large protein complexes. Our method is based on the level‐of‐detail concept, where we exploit three different abstractions combined in one visualization. Firstly, molecular surface abstraction exploits three different surfaces, solvent‐excluded surface (SES), Gaussian kernels and van der Waals spheres, combined as one surface by linear interpolation. Secondly, we introduce three shading abstraction levels and a method for creating seamless transitions between these representations. The SES representation with full shading and added contours stands in focus while on the other side a sphere representation of a cluster of atoms with constant shading and without contours provide the context. Thirdly, we propose a hierarchical abstraction based on a set of clusters formed on molecular atoms. All three abstraction models are driven by one importance function classifying the scene into the near‐, mid‐ and far‐field. Moreover, we introduce a methodology to render the entire molecule directly using the A‐buffer technique, which further improves the performance. The rendering performance is evaluated on series of molecules of varying atom counts. 相似文献
48.
《International journal of human-computer studies》2014,72(3):284-297
Analysis of the usability of an interactive system requires both an understanding of how the system is to be used and a means of assessing the system against that understanding. Such analytic assessments are particularly important in safety-critical systems as latent vulnerabilities may exist which have negative consequences only in certain circumstances. Many existing approaches to assessment use tasks or scenarios to provide explicit representation of their understanding of use. These normative user behaviours have the advantage that they clarify assumptions about how the system will be used but have the disadvantage that they may exclude many plausible deviations from these norms. Assessments of how a design fails to support these user behaviours can be a matter of judgement based on individual experience rather than evidence. We present a systematic formal method for analysing interactive systems that is based on constraints rather than prescribed behaviour. These constraints capture precise assumptions about what information resources are used to perform action. These resources may either reside in the system itself or be external to the system. The approach is applied to two different medical device designs, comparing two infusion pumps currently in common use in hospitals. Comparison of the two devices is based on these resource assumptions to assess consistency of interaction within the design of each device. 相似文献
49.
张建淳 《数码设计:surface》2014,(6):111-113
认知心理学介入到交互设计领域受到越来越多学者的关注,但是关于无意识的隐性记忆的介入却甚少被提及。,文章从隐性记忆的特征、隐性记忆介入交互设计的价值以及隐性记忆引导交互设计的应用三方面进行研究和探索,通过对目标群体用户隐性记忆的普遍性研究,找到更高效的设计来提高用户体验。 相似文献
50.
互联网改变了人们的生活习惯,也创造了新的商业模式。在竞争激烈的现代市场环境下,传统的营销模式已不能满足企业生存与发展的需要。网络口碑传播作为一种廉价的信息传播工具与可信度高的宣传媒介,已经引起了营销者的关注。而品牌作为企业的核心资产,企业要想塑造成功的品牌就应了解顾客的品牌认知。基于此,分析网络口碑传播对品牌认知的影响,构建基于品牌认知的网络口碑传播模型,提出企业在网络口碑传播中提高顾客的品牌认知的策略具有较好的现实意义。 相似文献