全文获取类型
收费全文 | 16390篇 |
免费 | 1912篇 |
国内免费 | 1037篇 |
专业分类
电工技术 | 499篇 |
技术理论 | 3篇 |
综合类 | 1471篇 |
化学工业 | 2459篇 |
金属工艺 | 419篇 |
机械仪表 | 596篇 |
建筑科学 | 1222篇 |
矿业工程 | 490篇 |
能源动力 | 572篇 |
轻工业 | 3579篇 |
水利工程 | 218篇 |
石油天然气 | 390篇 |
武器工业 | 106篇 |
无线电 | 1304篇 |
一般工业技术 | 1719篇 |
冶金工业 | 580篇 |
原子能技术 | 90篇 |
自动化技术 | 3622篇 |
出版年
2024年 | 154篇 |
2023年 | 549篇 |
2022年 | 755篇 |
2021年 | 900篇 |
2020年 | 802篇 |
2019年 | 729篇 |
2018年 | 630篇 |
2017年 | 677篇 |
2016年 | 690篇 |
2015年 | 713篇 |
2014年 | 1102篇 |
2013年 | 1022篇 |
2012年 | 1135篇 |
2011年 | 1259篇 |
2010年 | 908篇 |
2009年 | 878篇 |
2008年 | 830篇 |
2007年 | 971篇 |
2006年 | 747篇 |
2005年 | 661篇 |
2004年 | 584篇 |
2003年 | 485篇 |
2002年 | 393篇 |
2001年 | 299篇 |
2000年 | 272篇 |
1999年 | 241篇 |
1998年 | 162篇 |
1997年 | 125篇 |
1996年 | 122篇 |
1995年 | 113篇 |
1994年 | 95篇 |
1993年 | 62篇 |
1992年 | 48篇 |
1991年 | 32篇 |
1990年 | 35篇 |
1989年 | 15篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 13篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1961年 | 4篇 |
1959年 | 3篇 |
1956年 | 3篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
This paper discusses the application of a class of feed-forward Artificial Neural Networks (ANNs) known as Multi-Layer Perceptrons(MLPs) to two vision problems: recognition and pose estimation of 3D objects from a single 2D perspective view; and handwritten digit recognition. In both cases, a multi-MLP classification scheme is developed that combines the decisions of several classifiers. These classifiers operate on the same feature set for the 3D recognition problem whereas different feature types are used for the handwritten digit recognition. The backpropagationlearning rule is used to train the MLPs. Application of the MLP architecture to other vision problems is also briefly discussed. 相似文献
33.
34.
Krister Lindén 《Computers and the Humanities》2004,38(4):417-435
Word sense disambiguation automatically determines the appropriate senses of a word in context. We have previously shown that self-organized document maps have properties similar to a large-scale semantic structure that is useful for word sense disambiguation. This work evaluates the impact of different linguistic features on self-organized document maps for word sense disambiguation. The features evaluated are various qualitative features, e.g. part-of-speech and syntactic labels, and quantitative features, e.g. cut-off levels for word frequency. It is shown that linguistic features help make contextual information explicit. If the training corpus is large even contextually weak features, such as base forms, will act in concert to produce sense distinctions in a statistically significant way. However, the most important features are syntactic dependency relations and base forms annotated with part of speech or syntactic labels. We achieve 62.9% ± 0.73% correct results on the fine grained lexical task of the English SENSEVAL-2 data. On the 96.7% of the test cases which need no back-off to the most frequent sense we achieve 65.7% correct results. 相似文献
35.
基于FLANN的动态称重法 总被引:1,自引:0,他引:1
根据“逆模型”的思想 ,利用神经元网络良好的逼近能力 ,基于函数联接型神经网络 ( FLANN)的传感器动态补偿方法和最小二乘法 ,提出了一种车辆动态称重解决新方法 相似文献
36.
先进生产力的判断标准应该是经济效率标准、具体时空标准、人民利益标准、可持续发展标准的统一。先进生产力的三个本质特征:先进生产力是一个诸种先进生产要素综合作用的系统;先进生产力以先进的科学技术为载体;先进生产力具有量态和质态两种属性。 相似文献
37.
用B3LYP/6 31 1 + +G 方法研究了H2 S与HO2 自由基之间的氢键。发现了三个能量极小点。同时做了H2 S·HO2 的振动频率分析。计算预测了能量整体最小点的构型为带有 2个扭曲的氢键的五元环结构 相似文献
38.
Four experiments addressed the question of whether attention may be captured when the visual system is in the midst of an attentional blink (AB). Participants identified 2 target letters embedded among distractor letters in a rapid serial visual presentation sequence. In some trials, a square frame was inserted between the targets; as the only geometric object in the sequence, it constituted a singleton. Capture effects obtained when the AB was most severe and when it was over were compared. There were 3 main results. First, capture occurred even when the AB was crippling, suggesting that a singleton exogenously engaged attention even when processing of a previous target was continuing apace. Second, when the singleton contained the key target feature, capture effects were clearly manifest. Third, even when the singleton did not possess the key target feature, it still succeeded in capturing attention, although the effects were both feeble and fleeting. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
39.
This brief paper presents new conditions for the existence and design of reduced‐order linear functional state observers for linear systems with unknown inputs. Systematic procedures for the synthesis of reduced‐order functional observers are given. Numerical examples are given to illustrate the attractiveness and simplicity of the new design procedures. 相似文献
40.
研究四阶泛函微分方程x^(4)(t)+a1x^′′′(t)+a2x^′′(t)+a3x^′(t)+a4x(t)+g(t,x(t—τ))=p(t)的周期解问题.首先将该方程转变为四维的拟线性微分方程(组),得到该方程存在唯一周期解的充分条件;然后通过选取适当的李雅普诺夫函数,推导方程任一解的全局吸引性,并进一步得到方程周期解的全局吸引性.最后,通过实例证实了本文结果的正确性. 相似文献