全文获取类型
收费全文 | 455篇 |
免费 | 15篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 103篇 |
金属工艺 | 2篇 |
机械仪表 | 9篇 |
建筑科学 | 9篇 |
能源动力 | 5篇 |
轻工业 | 51篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 68篇 |
一般工业技术 | 84篇 |
冶金工业 | 86篇 |
自动化技术 | 44篇 |
出版年
2023年 | 4篇 |
2022年 | 25篇 |
2021年 | 20篇 |
2020年 | 15篇 |
2019年 | 11篇 |
2018年 | 11篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 18篇 |
2012年 | 25篇 |
2011年 | 30篇 |
2010年 | 17篇 |
2009年 | 13篇 |
2008年 | 21篇 |
2007年 | 23篇 |
2006年 | 14篇 |
2005年 | 28篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 5篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1998年 | 19篇 |
1997年 | 15篇 |
1996年 | 10篇 |
1995年 | 11篇 |
1994年 | 7篇 |
1993年 | 11篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有470条查询结果,搜索用时 15 毫秒
21.
Tracking an object in a sequence of images can fail due to partial occlusion or clutter. Robustness to occlusion can be increased by tracking the object as a set of "parts" such that not all of these are occluded at the same time. However, successful implementation of this idea hinges upon finding a suitable set of parts. In this paper we propose a novel segmentation, specifically designed to improve robustness against occlusion in the context of tracking. The main result shows that tracking the parts resulting from this segmentation outperforms both tracking parts obtained through traditional segmentations, and tracking the entire target. Additional results include a statistical analysis of the correlation between features of a part and tracking error, and identifying a cost function that exhibits a high degree of correlation with the tracking error. 相似文献
22.
Carmelo Cassisi Alfredo Ferro Rosalba Giugno Giuseppe Pigola Alfredo Pulvirenti 《Information Systems》2013
Clustering is a widely used unsupervised data mining technique. It allows to identify structures in collections of objects by grouping them into classes, named clusters, in such a way that similarity of objects within any cluster is maximized and similarity of objects belonging to different clusters is minimized. In density-based clustering, a cluster is defined as a connected dense component and grows in the direction driven by the density. The basic structure of density-based clustering presents some common drawbacks: (i) parameters have to be set; (ii) the behavior of the algorithm is sensitive to the density of the starting object; and (iii) adjacent clusters of different densities could not be properly identified. In this paper, we address all the above problems. Our method, based on the concept of space stratification, efficiently identifies the different densities in the dataset and, accordingly, ranks the objects of the original space. Next, it exploits such a knowledge by projecting the original data into a space with one more dimension. It performs a density based clustering taking into account the reverse-nearest-neighbor of the objects. Our method also reduces the number of input parameters by giving a guideline to set them in a suitable way. Experimental results indicate that our algorithm is able to deal with clusters of different densities and outperforms the most popular algorithms DBSCAN and OPTICS in all the standard benchmark datasets. 相似文献
23.
24.
25.
Water Resources Management - This paper presents a case study conducted in the Upper Argos River, in southeast Spain, to verify the applicability of the SWAT model for prediction of the water... 相似文献
26.
Arcidiacono C Diolaiti E Tordi M Ragazzoni R Farinato J Vernet E Marchetti E 《Applied optics》2004,43(22):4288-4302
The Layer-Oriented Simulation Tool (LOST) is a numerical simulation code developed for analysis of the performance of multiconjugate adaptive optics modules following a layer-oriented approach. The LOST code computes the atmospheric layers in terms of phase screens and then propagates the phase delays introduced in the natural guide stars' wave fronts by using geometrical optics approximations. These wave fronts are combined in an optical or numerical way, including the effects of wave-front sensors on measurements in terms of phase noise. The LOST code is described, and two applications to layer-oriented modules are briefly presented. We have focus on the Multiconjugate adaptive optics demonstrator to be mounted upon the Very Large Telescope and on the Near-IR-Visible Adaptive Interferometer for Astronomy (NIRVANA) interferometric system to be installed on the combined focus of the Large Binocular Telescope. 相似文献
27.
C Alli F Avanzini G Bettelli M Bonati F Colombo R Corso M Di Tullio MG Gentile L Sangalli E Taioli 《Canadian Metallurgical Quarterly》1992,6(4):281-286
The present study set out to assess the feasibility of long-term moderate dietary sodium restriction in patients with mild hypertension in general practice. After screening and a run-in phase of 6-8 weeks, a total of 77 previously undiagnosed mildly hypertensive patients were identified. Half of them were randomized to receive a few simple dietary instructions from their general practitioners in order to reduce salt usage; the others were randomized to receive no advice. The patients were followed up for 12 months with quarterly visits. A total of 56 patients (72.7%) completed the study, 26 on a low-sodium diet (LD) and 30 on their usual diet (UD). At each visit in the diet phase, patients provided 24h urine, which was analysed for volume and sodium concentration in order to assess their sodium intake. Blood pressure, heart the rate and body weight were recorded. The mean urinary sodium excretion for all diet phase visits overlapped in the two groups (177.0 +/- 32.9 vs. 169.3 +/- 49.4 mEq/24h respectively in the LD and UD groups). Nevertheless the mean systolic and diastolic blood pressures for all diet phase visits were significantly lower in the LD than in UD group (144.2 +/- 11.1/91.6 +/- 6.4 and 148.0 +/- 13.7/95.6 +/- 4.7 mmHg respectively, P less than 0.01). Our data suggest that it is not feasible at present to reduce sodium intake in mild hypertensives with simple and inexpensive dietary instructions, the only ones suitable for widespread application in general practice. 相似文献
28.
Carmelo Del Valle Antonio Márquez Irene Barba 《Journal of Intelligent Manufacturing》2010,21(1):165-174
This work presents a constraint satisfaction problem (CSP) model for the planning and scheduling of disassembly and assembly
tasks when repairing or substituting faulty parts. The problem involves not only the ordering of assembly and disassembly
tasks, but also the selection of them from a set of alternatives. The goal of the plan is the minimization of the total repairing
time, and the model considers, apart from the durations and resources used for the assembly and disassembly tasks, the necessary
delays due to the change of configuration in the machines, and to the transportation of intermediate subassemblies between
different machines. The problem considers that sub-assemblies that do not contain the faulty part are nor further disassembled,
but allows non-reversible and parallel repair plans. The set of all feasible repair plans are represented by an extended And/Or graph. This extended representation embodies all of the constraints of the problem, such as temporal and resource constraints
and those related to the selection of tasks for obtaining a correct plan. 相似文献
29.
Tiziana Nardo Valeria Chiono Piergiorgio Gentile Maryam Tabrizian Gianluca Ciardelli 《国际聚合物材料杂志》2016,65(14):741-750
Poly(DL-lactide-co-ε-caprolactone) (PLCL) and poly(DL-lactide-co-glycolide) (PLGA) blends of various compositions were prepared. Fractured sections of PLCL/PLGA blends did not evidence phase separation and blend glass transition temperatures suggested some degree of blend compatibility. The elastic modulus showed a negative deviation from the additive law of mixture. Superior biocompatibility in terms of fibroblast NIH 3T3 cell adhesion and proliferation, better mechanical properties, and a more homogeneous phase were obtained with PLCL/PLGA 25/75 blend. Rapid degradation of PLCL phase (4–8 weeks) in PLCL/PLGA 25/75 blend led to a porous structure, which makes it a potential candidate for drug delivery systems. 相似文献
30.
Influence of catalyst pretreatments on volatile organic compounds oxidation over gold/iron oxide 总被引:4,自引:0,他引:4
Simona Minic Salvatore Scir Carmelo Crisafulli Signorino Galvagno 《Applied catalysis. B, Environmental》2001,34(4):277-285
This paper reports a study on the influence of calcination pretreatments on the catalytic behaviour of the Au/iron oxide system towards the combustion of some representative volatile organic compounds (2-propanol, ethanol, methanol, acetone and toluene). The catalytic activity of Au/Fe2O3 samples towards the total oxidation to CO2 has been found to be strongly dependent on the catalyst pretreatment, decreasing on increasing the calcination temperature. On the basis of characterisation data (XPS, FT-IR, XRD, BET surface area) it has been proposed that the catalytic behaviour is related to the gold state and/or the iron oxide phase. It appears plausible to suggest that the gold oxidation state and/or the particle size play a key role in the catalytic combustion of volatile organic compounds. 相似文献