全文获取类型
收费全文 | 2926篇 |
免费 | 167篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 40篇 |
综合类 | 2篇 |
化学工业 | 723篇 |
金属工艺 | 69篇 |
机械仪表 | 65篇 |
建筑科学 | 96篇 |
矿业工程 | 5篇 |
能源动力 | 80篇 |
轻工业 | 313篇 |
水利工程 | 8篇 |
石油天然气 | 20篇 |
无线电 | 220篇 |
一般工业技术 | 524篇 |
冶金工业 | 403篇 |
原子能技术 | 20篇 |
自动化技术 | 508篇 |
出版年
2023年 | 26篇 |
2022年 | 82篇 |
2021年 | 96篇 |
2020年 | 53篇 |
2019年 | 62篇 |
2018年 | 91篇 |
2017年 | 86篇 |
2016年 | 112篇 |
2015年 | 71篇 |
2014年 | 109篇 |
2013年 | 205篇 |
2012年 | 163篇 |
2011年 | 205篇 |
2010年 | 121篇 |
2009年 | 164篇 |
2008年 | 151篇 |
2007年 | 140篇 |
2006年 | 119篇 |
2005年 | 85篇 |
2004年 | 84篇 |
2003年 | 87篇 |
2002年 | 56篇 |
2001年 | 41篇 |
2000年 | 45篇 |
1999年 | 43篇 |
1998年 | 106篇 |
1997年 | 64篇 |
1996年 | 62篇 |
1995年 | 38篇 |
1994年 | 37篇 |
1993年 | 24篇 |
1992年 | 20篇 |
1991年 | 15篇 |
1990年 | 17篇 |
1989年 | 18篇 |
1988年 | 10篇 |
1987年 | 19篇 |
1986年 | 11篇 |
1985年 | 19篇 |
1984年 | 14篇 |
1983年 | 21篇 |
1982年 | 11篇 |
1981年 | 12篇 |
1980年 | 5篇 |
1979年 | 12篇 |
1978年 | 7篇 |
1977年 | 11篇 |
1976年 | 18篇 |
1975年 | 5篇 |
1973年 | 6篇 |
排序方式: 共有3096条查询结果,搜索用时 15 毫秒
141.
Vivian Maria Carminato Blanco Lucas Tadeu Fuess Marcelo Zaiat 《International Journal of Hydrogen Energy》2017,42(17):12181-12196
Biohydrogen (bioH2) production via dark fermentation is an attractive approach to overcome the drawbacks of conventional hydrogen production methods and represents a preliminary alternative for the management of organic wastes. Fundamental studies are still required to enhance the performance of bioH2 production systems, with emphasis on the development of novel reactor configurations. The anaerobic structured-bed reactor (ASTBR) is a recently developed configuration with great potential for bioH2 production, although operating strategies are still required to minimize biomass washout in such systems. In this context, calcium dosing has been investigated as a strategy to enhance both biomass retention and bioH2 production rates in the ASTBR. The present study employed varying COD/calcium ratios (4423, 2079, 1357, 1012, 884, and 632) in continuous experiments under mesophilic conditions (25 °C). Calcium dosing effectively enhanced biomass retention within the ASTBR, directly increasing the availability of metabolic energy for different metabolic pathways rather than cell synthesis. An optimal COD/calcium ratio of 1360 was mathematically estimated for bioH2 production, which is consistent with the results obtained experimentally. The specific organic loading rate (SOLR) was better controlled at this ratio, indicating the establishment of balanced conditions in terms of substrate availability and biomass concentration. Conversely, bioH2 production was severely impaired at COD/calcium values below and above the optimal range, most likely due to enhancement of the homoacetogenic pathway as a result of unbalanced conditions in the SOLR. Furthermore, biomass accumulation did not strongly affect the mean residence time of the ASTBR, facilitating its robust and enhanced solid retention. 相似文献
142.
Miguel A. Otaduy Rasmus Tamstorf Denis Steinemann Markus Gross 《Computer Graphics Forum》2009,28(2):559-568
We present an algorithm for robust and efficient contact handling of deformable objects. By being aware of the internal dynamics of the colliding objects, our algorithm provides smooth rolling and sliding, stable stacking, robust impact handling, and seamless coupling of heterogeneous objects, all in a unified manner. We achieve dynamicsawareness through a constrained dynamics formulation with implicit complementarity constraints, and we present two major contributions that enable an efficient solution of the constrained dynamics problem: a time stepping algorithm that robustly ensures non-penetration and progressively refines the formulation of constrained dynamics, and a new solver for large mixed linear complementarity problems, based on iterative constraint anticipation. We show the application of our algorithm in challenging scenarios such as multi-layered cloth moving at high velocities, or colliding deformable solids simulated with large time steps. 相似文献
143.
An electronic panel formed by an electronic nose, an electronic tongue and an electronic eye has been successfully used to evaluate the organoleptic characteristics of red wines vinified using different extraction techniques and micro-oxygenation methods and bottled using closures of different oxygen transmission rates (OTR). 相似文献
144.
Characterization of recycled styrene butadiene rubber ground tire rubber: Combining X‐ray fluorescence,differential scanning calorimetry,and dynamical thermal analysis for quality control
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Appraisal of the main rubber characterization techniques for styrene butadiene rubber (SBR) was performed on standard SBR samples as well as recycled ground tire rubber (GTR) from an industrial tire recycling facility, containing a blend of SBR and natural rubber. The aim of the work was to provide additional information relevant to quality control in the field of rubber recycling. Benchmark characterization of industrial samples by inductively coupled plasma optical emission spectrometry, atomic absorption spectrometry, solid‐state proton nuclear magnetic resonance, and elemental (CHNS) analysis are reported. X‐ray fluorescence spectrometry is shown to be rapid and quantitative for determining the zinc content in an industrial context. Thermogravimetric analysis, already used to determine carbon black and inorganic material content in rubbers and GTR, is recommended for determination of monomer weight ratios of SBR sources not containing other rubbers, but not for GTR. Differential scanning calorimetry (DSC) measurements of the glass‐transition show that changes in monomer ratio affect glass‐transition temperature values, and therefore, DSC can be used to detect changes in rubber composition from batch to batch. These results show that DSC and X‐ray fluorescence spectroscopy characterization techniques can be used for GTR and may lead to more thorough and rapid quality control procedures of these complex samples. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42692. 相似文献
145.
Cassio Eduardo Lima de Paiva Jose Lulz Antunes de Oliveira e Sousa Luiz Carlos de Almeida Paulo RobertoAguiar Luiz Femando de Melo Correia Juliana Silva Watanabe Rodrigo Moreira de Carvalho Creso deFranco Peixoto Denis Palomo Paschoalin 《土木工程与建筑:英文版》2013,(8):964-972
The EFVM (Vitoria Minas Railroad) is one of the main railways in Brazil. It transports freight trains of ore, 220 wagons each. These wagons have 2 boogies of 2 axles each and 32 metric tons on metre gauge. Elastic strains were measured on a special part of this railway due to these trains. The main load to evaluate stresses and strains was a G 16 Locomotive, a C-C kind from Vale, a Brazilian Company. The measurements were obtained by dynamic deflectometer installed on a main line of this railway, near Ipatinga, a city from Minas Gerais, one of Brazil states. This track was equipped to obtain stresses under an equal repeated static load A simulation of the stresses was made under critical strain by Ferrovia 1.0 software. It was also made an evaluation of unequal results from neighbor sleepers taking in comparison two equipped parts of this railway, one with compacted ballast and no compaction to the other. The results were strain limited, avoiding breakage or damage to the studied rails. This work analyses these measurements focusing on the improvement of track quality. 相似文献
146.
Csaba M. Jzsa Gza Kolumbn Antonio M. Vidal Francisco J. Martínez‐Zaldívar Alberto Gonzlez 《Concurrency and Computation》2015,27(17):4993-5018
Multiple‐input multiple‐output (MIMO) systems have attracted considerable attention in wireless communications because they offer a significant increase in data throughput and link coverage without additional bandwidth requirement or increased transmit power. The price that has to be paid is the increased complexity of hardware components and algorithms. The sphere detector (SD) algorithm solves the problem of maximum likelihood (ML) detection for MIMO channels by significantly reducing the search space of possible solutions. The main drawback of the SD algorithm is in its sequential nature, consequently, running it on massively parallel architectures (MPAs) is very inefficient. In order to overcome the drawbacks of the SD algorithm, a new parallel sphere detector (PSD) algorithm is proposed. It implements a novel hybrid tree search method, where the algorithm parallelism is assured by the efficient combination of depth‐first search and breadth‐first search algorithms. A path metric‐based parallel sorting is employed at each intermediate stage. The PSD algorithm is able to adjust its memory requirements and extent of parallelism to fit a wide range of parallel architectures. Mapping details for MPAs are proposed by giving the details of thread dependent, highly parallel building blocks of the algorithm. Based on the building blocks proposed, a mapping to general‐purpose graphics processing unit is provided, and its performance is evaluated. In order to achieve high‐throughput, several levels of parallelism are introduced, and different scheduling strategies are considered. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
147.
Iskandar Abdullaev Alexander Platonov Denis Sorokin 《The International journal of environmental studies》2013,70(1):151-168
Contemporary water management decisions use many sources and forms of data. The paper discusses the implementation results of data management activities in the water sector carried out in five countries of the Central Asia region. Geoinformation systems, remote sensing tools and databases have been applied worldwide for improving water resources management with differing levels of success. Water management organisations, equipped with data management tools will have better capacities to adapt their decision-making in the changing availability and scarcity of water resources. Application of data management tools for improving collection, storage and processing of data and information are a first step towards improved water governance. 相似文献
148.
149.
S. O. Denis Russell 《Civil Engineering and Environmental Systems》2013,30(1):9-12
The drive to develop expert systems is forcing would-be developers to examine and make explicit the mental processes which experts use. Much of what an expert actually does is carried out intuitively and without any conscious thought. The procedures and mental processes used in civil engineering design involve a ‘creative phase’, where the design first takes shape and then ‘evolves’, and a ‘checking phase’ to ensure that it will be satisfactory. Experience and judgement play large roles in both phases. In this paper, the role of experience and how it is gained are examined. Defining experience is important not only for expert systems designers but also for the education and training of future design engineers. 相似文献