全文获取类型
收费全文 | 2682篇 |
免费 | 195篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 59篇 |
综合类 | 1篇 |
化学工业 | 816篇 |
金属工艺 | 17篇 |
机械仪表 | 79篇 |
建筑科学 | 104篇 |
矿业工程 | 2篇 |
能源动力 | 83篇 |
轻工业 | 422篇 |
水利工程 | 27篇 |
石油天然气 | 5篇 |
无线电 | 229篇 |
一般工业技术 | 380篇 |
冶金工业 | 83篇 |
原子能技术 | 12篇 |
自动化技术 | 559篇 |
出版年
2023年 | 24篇 |
2022年 | 57篇 |
2021年 | 183篇 |
2020年 | 90篇 |
2019年 | 84篇 |
2018年 | 109篇 |
2017年 | 84篇 |
2016年 | 135篇 |
2015年 | 90篇 |
2014年 | 117篇 |
2013年 | 201篇 |
2012年 | 168篇 |
2011年 | 218篇 |
2010年 | 153篇 |
2009年 | 179篇 |
2008年 | 125篇 |
2007年 | 129篇 |
2006年 | 108篇 |
2005年 | 87篇 |
2004年 | 65篇 |
2003年 | 57篇 |
2002年 | 59篇 |
2001年 | 35篇 |
2000年 | 28篇 |
1999年 | 24篇 |
1998年 | 31篇 |
1997年 | 23篇 |
1996年 | 30篇 |
1995年 | 16篇 |
1994年 | 28篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 18篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 11篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1971年 | 2篇 |
1965年 | 2篇 |
1909年 | 2篇 |
排序方式: 共有2878条查询结果,搜索用时 218 毫秒
111.
K. Erik J. Olofsson Anton Soppelsa Tommaso Bolzonella Giuseppe Marchiori 《Control Engineering Practice》2013,21(7):917-929
Input–output datasets from two magnetic confinement fusion (MCF) experiments of the reversed-field pinch (RFP) type are examined. The RFP datasets, which are samples of the distributed magnetic field dynamics, are naturally divided into many smaller batches due to the pulsed-plasma operation of the experiments. The two RFP experiments considered are (i) EXTRAP T2R (T2R) with 64 inputs and 64 outputs and (ii) RFX-mod (RFX) with 192 inputs and 192 outputs. Both T2R and RFX are magnetohydrodynamically unstable and operates under magnetic feedback with optional dither injection. Using subspace system identification techniques and randomised cross-validation (CV) methods to minimise the generalisation error, state-space orders of the empirical systems are suggested. These system orders are compared to “stabilisation diagrams” commonly used in experimental modal analysis practice. The relation of the CV system order to the decay of the singular values from the subspace method is observed. Both (i) stable vacuum diffusion and (ii) unstable plasma response datasets are analysed. Apparent simulation and prediction errors are quantified for both cases using a deviation-accounted-for index. These results are purely data-driven. A simple approach towards exploitation of the subspace techniques for finite-element model refinement and data confrontation is presented. 相似文献
112.
113.
Marco Sanduzzi Zamparelli Debora Compare Pietro Coccoli Alba Rocco Olga Maria Nardone Giuseppe Marrone Antonio Gasbarrini Antonio Grieco Gerardo Nardone Luca Miele 《International journal of molecular sciences》2016,17(8)
The prevalence of metabolic disorders, such as type 2 diabetes (T2D), obesity, and non-alcoholic fatty liver disease (NAFLD), which are common risk factors for cardiovascular disease (CVD), has dramatically increased worldwide over the last decades. Although dietary habit is the main etiologic factor, there is an imperfect correlation between dietary habits and the development of metabolic disease. Recently, research has focused on the role of the microbiome in the development of these disorders. Indeed, gut microbiota is implicated in many metabolic functions and an altered gut microbiota is reported in metabolic disorders. Here we provide evidence linking gut microbiota and metabolic diseases, focusing on the pathogenetic mechanisms underlying this association. 相似文献
114.
Elia Bari Ilaria Roato Giuseppe Perale Filippo Rossi Tullio Genova Federico Mussano Riccardo Ferracini Marzio Sorlini Maria Luisa Torre Sara Perteghella 《International journal of molecular sciences》2021,22(8)
SmartBone® (SB) is a biohybrid bone substitute advantageously proposed as a class III medical device for bone regeneration in reconstructive surgeries (oral, maxillofacial, orthopedic, and oncology). In the present study, a new strategy to improve SB osteoinductivity was developed. SB scaffolds were loaded with lyosecretome, a freeze-dried formulation of mesenchymal stem cell (MSC)-secretome, containing proteins and extracellular vesicles (EVs). Lyosecretome-loaded SB scaffolds (SBlyo) were prepared using an absorption method. A burst release of proteins and EVs (38% and 50% after 30 min, respectively) was observed, and then proteins were released more slowly with respect to EVs, most likely because they more strongly adsorbed onto the SB surface. In vitro tests were conducted using adipose tissue-derived stromal vascular fraction (SVF) plated on SB or SBlyo. After 14 days, significant cell proliferation improvement was observed on SBlyo with respect to SB, where cells filled the cavities between the native trabeculae. On SB, on the other hand, the process was still present, but tissue formation was less organized at 60 days. On both scaffolds, cells differentiated into osteoblasts and were able to mineralize after 60 days. Nonetheless, SBlyo showed a higher expression of osteoblast markers and a higher quantity of newly formed trabeculae than SB alone. The quantification analysis of the newly formed mineralized tissue and the immunohistochemical studies demonstrated that SBlyo induces bone formation more effectively. This osteoinductive effect is likely due to the osteogenic factors present in the lyosecretome, such as fibronectin, alpha-2-macroglobulin, apolipoprotein A, and TGF-β. 相似文献
115.
Giuseppe Della Penna Daniele Magazzeni Sergio Orefice 《Knowledge and Information Systems》2012,30(3):667-692
The Spatial Relation Query (SRQ) tool is a graphical software environment, supported by a SQL-like language, which enables
users to perform information extraction driven by the visual appearance and the spatial arrangement of the information. The
tool has been initially customised to work on specific application domains, like web pages and geospatial data. In this paper,
we present the theoretical formalisation of the visual information extraction (VIE) task and accordingly the redesign of the
SRQ tool, which is now a full-featured, general-purpose information extraction system. Moreover, we show a new application
of the VIE framework to the analysis and visual information extraction from PDF files. 相似文献
116.
Daniela dell'Oro Francesco Casamassima Giuseppe Gesualdo Marco Iammarino Paolo Mambelli Valeria Nardelli 《International Journal of Food Science & Technology》2014,49(5):1391-1400
The aim of this study was to develop and validate an efficient analytical method based on gas chromatography/tandem mass spectrometry (GC/MS/MS) for detection and quantification of six pyrethroids residues (Phenothrin, Permethrin, Cyfluthrin, Cypermethrin, Deltamethrin and Fenvalerate) in chicken eggs. The method was based on a preliminary liquid–liquid extraction of albumen‐free yolk samples, followed by a clean‐up by solid‐phase extraction. GC/MS/MS analyses were carried out in the selected reaction monitoring mode. Validation parameters such as specificity, detection capability, decision limit, precision, recovery, stability and ruggedness were determined, resulting in compliance with Decision 2002/657/EC. No complicated apparatus are required; moreover, low volumes of organic solvents and a nonintensive manual labour are required. These low costs and simple procedure, based on rapid and safe operations, may represent a useful tool in the routine analysis of pyrethroids pesticides, in the place of the currently used conventional techniques. 相似文献
117.
Mathias Bürger Giuseppe Notarstefano Francesco Bullo Frank Allgöwer 《Automatica》2012,48(9):2298-2304
In this paper we propose a novel distributed algorithm to solve degenerate linear programs on asynchronous peer-to-peer networks with distributed information structures. We propose a distributed version of the well-known simplex algorithm for general degenerate linear programs. A network of agents, running our algorithm, will agree on a common optimal solution, even if the optimal solution is not unique, or will determine infeasibility or unboundedness of the problem. We establish how the multi-agent assignment problem can be efficiently solved by means of our distributed simplex algorithm. We provide simulations supporting the conjecture that the completion time scales linearly with the diameter of the communication graph. 相似文献
118.
Renato Colle Giuseppe Grosso Alberto Ronzani Massimo Gazzano Vincenzo Palermo 《Carbon》2012,50(3):1332-1337
We describe the self-assembly of soluble, chemically modified fullerene [6,6]-phenyl C61 butyric acid methyl ester (PCBM) into a new crystalline phase where the C60 moieties are arranged in parallel layers. Minimum C60 center-to-center distance is 10 Å within the layers, and up to 15 Å perpendicular to the layers. Highly anisotropic, mesoscopic hexagonal crystals of this material, with a lateral size of many microns and a thickness below 1 μm, are obtained from chloroform solution by solvent vapor annealing, and characterized by optical microscopy and X-ray diffraction. The crystalline structure is deduced combining experimental data with molecular modeling and ab initio calculations. The large difference in C60–C60 spacing indicates a high anisotropy in electrical and charge transport properties of this new phase. 相似文献
119.
120.