全文获取类型
收费全文 | 3973篇 |
免费 | 353篇 |
国内免费 | 274篇 |
专业分类
电工技术 | 212篇 |
综合类 | 489篇 |
化学工业 | 283篇 |
金属工艺 | 67篇 |
机械仪表 | 203篇 |
建筑科学 | 292篇 |
矿业工程 | 100篇 |
能源动力 | 85篇 |
轻工业 | 168篇 |
水利工程 | 138篇 |
石油天然气 | 136篇 |
武器工业 | 104篇 |
无线电 | 588篇 |
一般工业技术 | 447篇 |
冶金工业 | 209篇 |
原子能技术 | 17篇 |
自动化技术 | 1062篇 |
出版年
2024年 | 7篇 |
2023年 | 39篇 |
2022年 | 69篇 |
2021年 | 90篇 |
2020年 | 102篇 |
2019年 | 101篇 |
2018年 | 84篇 |
2017年 | 122篇 |
2016年 | 145篇 |
2015年 | 151篇 |
2014年 | 220篇 |
2013年 | 281篇 |
2012年 | 267篇 |
2011年 | 318篇 |
2010年 | 208篇 |
2009年 | 229篇 |
2008年 | 237篇 |
2007年 | 267篇 |
2006年 | 233篇 |
2005年 | 191篇 |
2004年 | 162篇 |
2003年 | 168篇 |
2002年 | 124篇 |
2001年 | 103篇 |
2000年 | 100篇 |
1999年 | 66篇 |
1998年 | 52篇 |
1997年 | 64篇 |
1996年 | 67篇 |
1995年 | 38篇 |
1994年 | 44篇 |
1993年 | 37篇 |
1992年 | 27篇 |
1991年 | 21篇 |
1990年 | 33篇 |
1989年 | 16篇 |
1988年 | 14篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1964年 | 5篇 |
1963年 | 4篇 |
1960年 | 3篇 |
1957年 | 4篇 |
1955年 | 6篇 |
排序方式: 共有4600条查询结果,搜索用时 0 毫秒
41.
《国际计算机数学杂志》2012,89(5):803-811
A combination of microarrays with classification methods is a promising approach to supporting clinical management decisions in oncology. The aim of this paper is to systematically benchmark the role of classification models. Each classification model is a combination of one feature extraction method and one classification method. We consider four feature extraction methods and five classification methods, from which 20 classification models can be derived. The feature extraction methods are t-statistics, non-parametric Wilcoxon statistics, ad hoc signal-to-noise statistics, and principal component analysis (PCA), and the classification methods are Fisher linear discriminant analysis (FLDA), the support vector machine (SVM), the k nearest-neighbour classifier (kNN), diagonal linear discriminant analysis (DLDA), and diagonal quadratic discriminant analysis (DQDA). Twenty randomizations of each of three binary cancer classification problems derived from publicly available datasets are examined. PCA plus FLDA is found to be the optimal classification model. 相似文献
42.
在地质统计学的概念及相关理论的基础上,分析了多源遥感信息的特点及分类。将地质统计学引入遥感信息融合中,按时序获取不同传感器的观测信息并依据相关准则进行自动分析,完成了多传感器的状态估计和决策的信息处理过程。利用地质统计学的变差函数和克里金法对多源遥感信息进行空间特征的融合,提高了遥感信息的使用率,达到了准确预测和估计地质状态的目的。 相似文献
43.
针对车牌的边界定位不准确和伪车牌较多的问题,提出了一种边缘分析和颜色统计相结合的车牌精确定位的新框架。该框架主要分为预处理、粗定位、精确定位和伪车牌排除四个模块。对图像作边缘检测和二值化等预处理,用投影法粗定位出候选区域,利用候选区域及其周围的边缘和颜色的信息实现车牌的精确定位。对于定位结果有多个候选区域的情况,对候选区域进行排序,再将排序结果按顺序传入字符分割模块,从而有效排除非车牌区域的影响。实验结果表明,该方法精确度和准确率高、实时性强,适用于不同的应用场合。 相似文献
44.
统计过程控制在软件工程中的应用 总被引:1,自引:0,他引:1
统计过程控制已经在制造业取得了成功的应用,近年在软件工程方面的应用也不断上升。本文通过分析这些指标数据,找出软件过程中各个阶段的不确定因素,并采取适当措施来保证软件过程处于统计意义下的受控状态,从而达到保证软件质量、提高软件生产效率的目的。 相似文献
45.
企业统计是生产经营成果化、数量化的数字表现,是经济社会各项主要统计指标的源头数据之一。因此强化企业统计,加快统计信息网络建设,提高综合统计人员的素质,对企业的经营、对政府的宏观调控有着重要意义。 相似文献
46.
Often quantitative data in the social sciences have only ordinal justification. Problems of interpretation can arise when least squares multiple regression (LSMR) is used with ordinal data. Two ordinal alternatives are discussed, dominance-based ordinal multiple regression (DOMR) and proportional odds multiple regression. The Q2 statistic is introduced for testing the omnibus null hypothesis in DOMR. A simulation study is discussed that examines the actual Type I error rate and power of Q2 in comparison to the LSMR omnibus F test under normality and non-normality. Results suggest that Q2 has favorable sampling properties as long as the sample size-to-predictors ratio is not too small, and Q2 can be a good alternative to the omnibus F test when the response variable is non-normal. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
47.
The proportion of elderly in the population is continuing to increase, placing additional demands on highly competitive medical budgets. The management of the care of the elderly within hospitals can be assisted by the accurate modelling of the length of stay of patients in hospital. This paper uses conditional phase‐type distributions for modelling the length of stay of a group of elderly patients in hospital. The model incorporates the use of Bayesian belief networks with Coxian phase‐type distributions, a special type of Markov model that describes the duration of stay in hospital as a process consisting of a sequence of latent phases. The incorporation of the Bayesian belief network in the model permits the inclusion of additional patient information which may provide a better understanding of the system, in particular the incorporation of any potential causal information that may exist in the data. 相似文献
48.
R. P. Agarwal D. O'Regan I. Rach
nkov S. Stan
k 《Computers & Mathematics with Applications》2003,46(12):1799-1826
The existence of solutions for singular higher-order differential equations with the Lidstone or the (n,p) boundary conditions is proved. The right-hand sides of differential equations can have singularities in the zero value of their phase variables and so higher derivatives of solutions changing their signs can pass through these singularities. Proofs are based on the method of a priori estimates, the degree theory arguments and on Vitali's convergence theorem. 相似文献
49.
On Advances in Statistical Modeling of Natural Images 总被引:15,自引:0,他引:15
A. Srivastava A.B. Lee E.P. Simoncelli S.-C. Zhu 《Journal of Mathematical Imaging and Vision》2003,18(1):17-33
Statistical analysis of images reveals two interesting properties: (i) invariance of image statistics to scaling of images, and (ii) non-Gaussian behavior of image statistics, i.e. high kurtosis, heavy tails, and sharp central cusps. In this paper we review some recent results in statistical modeling of natural images that attempt to explain these patterns. Two categories of results are considered: (i) studies of probability models of images or image decompositions (such as Fourier or wavelet decompositions), and (ii) discoveries of underlying image manifolds while restricting to natural images. Applications of these models in areas such as texture analysis, image classification, compression, and denoising are also considered. 相似文献
50.
While many implementations of Bayesian neural networks use large, complex hierarchical priors, in much of modern Bayesian statistics, noninformative (flat) priors are very common. This paper introduces a noninformative prior for feed-forward neural networks, describing several theoretical and practical advantages of this approach. In particular, a simpler prior allows for a simpler Markov chain Monte Carlo algorithm. Details of MCMC implementation are included. 相似文献