全文获取类型
收费全文 | 1430篇 |
免费 | 87篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 19篇 |
化学工业 | 318篇 |
金属工艺 | 31篇 |
机械仪表 | 21篇 |
建筑科学 | 57篇 |
矿业工程 | 1篇 |
能源动力 | 33篇 |
轻工业 | 252篇 |
水利工程 | 6篇 |
石油天然气 | 2篇 |
无线电 | 108篇 |
一般工业技术 | 247篇 |
冶金工业 | 118篇 |
原子能技术 | 2篇 |
自动化技术 | 309篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 19篇 |
2021年 | 39篇 |
2020年 | 24篇 |
2019年 | 28篇 |
2018年 | 48篇 |
2017年 | 47篇 |
2016年 | 52篇 |
2015年 | 35篇 |
2014年 | 73篇 |
2013年 | 107篇 |
2012年 | 109篇 |
2011年 | 106篇 |
2010年 | 85篇 |
2009年 | 78篇 |
2008年 | 81篇 |
2007年 | 68篇 |
2006年 | 58篇 |
2005年 | 51篇 |
2004年 | 43篇 |
2003年 | 41篇 |
2002年 | 34篇 |
2001年 | 30篇 |
2000年 | 25篇 |
1999年 | 29篇 |
1998年 | 30篇 |
1997年 | 22篇 |
1996年 | 15篇 |
1995年 | 17篇 |
1994年 | 17篇 |
1993年 | 19篇 |
1992年 | 15篇 |
1991年 | 2篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1524条查询结果,搜索用时 15 毫秒
1.
The present paper studies a feedback regulation problem that arises in at least two different biological applications. The feedback regulation problem under consideration may be interpreted as an adaptive control problem for tuning bifurcation parameters, and it has not been studied in the control literature. The goal of the paper is to formulate this problem and to present some preliminary results. 相似文献
2.
International Journal of Computer Vision - 相似文献
3.
André Girard Pierre Dominique Lansard Bernard Liau Anne Marie Mongeon Jean Luc Thibault 《电信纪事》1991,46(5-6):335-350
Classical hierarchical routing in telephone networks is extended to a wider class called out-of-chain routing in such a way that some useful properties of hierarchical routing are retained. This new routing pattern offers more potential paths than the fixed hierarchical one and can be introduced as a dynamic routing where the fixed alternate sequences change at some predetermined instants during the day. The effect of this new routing pattern on the network performances is examined. The main topic of this paper is to present heuristic methods used to optimise such routings in large networks. We show on artificial networks that the throughput of a given network can be significantly improved by suitable routing choices. We demonstrate that the integration of routing changes within a multihour dimensioning process is possible but the lack of realistic data does not permit at this time to quantify the value of routing optimization on real networks. 相似文献
4.
5.
We study the behavior of disk assemblies with a variable disorder distribution. The packing is first consolidated and then continuously tilted very slowly. The amount of displaced disks for each tilted angle is recorded. Large displacements of the disks can occur due to some local or global mechanical instabilities. The definition of neighboring disks is based on radical (extension of Voronoï) tessellation rules to decompose, in a unique and perfectly defined manner, the two-dimensional space for polydisperse disks. In this way, by comparing the characteristics of stability for one disk to the neighboring ones for local ordered cluster, we can predict the global amount of displaced disks. Some tilting cycles have been performed to check the correlation between the instability of the packing structure (collective displacements) with micro and macro order parameters. 相似文献
6.
Impact of apolipoprotein E polymorphism on lipoproteins and risk of myocardial infarction. The ECTIM Study 总被引:2,自引:0,他引:2
G Luc JM Bard D Arveiler A Evans JP Cambou A Bingham P Amouyel P Schaffer JB Ruidavets F Cambien 《Canadian Metallurgical Quarterly》1994,14(9):1412-1419
Human apolipoprotein (apo) E, a polymorphic protein with three common alleles, epsilon 2, epsilon 3, and epsilon 4, plays an important role in lipoprotein metabolism. This article describes the association of this polymorphism with lipids, apolipoproteins, and lipoproteins with a particular regard to lipoprotein particles, as defined by their apolipoprotein content, as well as the risk of myocardial infarction in a multicenter population-based case-control study (ECTIM study). In the ECTIM study, 574 male patients aged 25 to 64 were examined 3 to 9 months after myocardial infarction in four regions participating in the World Health Organization MONICA project: Belfast (Northern Ireland) and Lille, Strasbourg, and Toulouse (France). Control subjects (n = 722) were randomly selected from the regional populations. The distribution of apoE phenotypes was significantly different across the four control samples (P = .04), with a higher frequency of the epsilon 4 allele in Belfast (14.3%) than in Toulouse (8.2%). The association of apoE polymorphism with biological measurements was studied in the control groups (n = 640) after men with coronary heart disease or those taking hypolipidemic drugs were omitted, with the apoE3/3 phenotype as a reference after adjustment for concomitant factors. Individuals carrying the epsilon 2 allele had lower levels of plasma cholesterol, low-density lipoprotein cholesterol (LDL-C), and apoB and higher levels of triglycerides, very-low-density lipoprotein cholesterol (VLDL-C), apoC-III, apoE, lipoprotein (Lp) C-III:B, and Lp E:B. However, the effect of the epsilon 2 allele on triglyceride, VLDL-C, apoE, and Lp E:B parameters was heterogeneous across the populations.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
7.
8.
A model for atmospheric pollutant transport is proposed considering an advection–diffusion–reaction equation. A splitting method is used to decouple the advection, diffusion and reaction parts. A scheme based on finite volume, finite difference and backward differentiation formula is used for solving an atmospheric transport-chemistry problem. 相似文献
9.
Fabrice Rousselle Petrik Clarberg Luc Leblanc Victor Ostromoukhov Pierre Poulin 《The Visual computer》2008,24(7-9):465-474
We present an efficient method for importance sampling the product of multiple functions. Our algorithm computes a quick approximation of the product on the fly, based on hierarchical representations of the local maxima and averages of the individual terms. Samples are generated by exploiting the hierarchical properties of many low-discrepancy sequences, and thresholded against the estimated product. We evaluate direct illumination by sampling the triple product of environment map lighting, surface reflectance, and a visibility function estimated per pixel. Our results show considerable noise reduction compared to existing state-of-the-art methods using only the product of lighting and BRDF. 相似文献
10.
Luc Pronzato Author Vitae 《Automatica》2008,44(2):303-325
This paper traces the strong relations between experimental design and control, such as the use of optimal inputs to obtain precise parameter estimation in dynamical systems and the introduction of suitably designed perturbations in adaptive control. The mathematical background of optimal experimental design is briefly presented, and the role of experimental design in the asymptotic properties of estimators is emphasized. Although most of the paper concerns parametric models, some results are also presented for statistical learning and prediction with nonparametric models. 相似文献