全文获取类型
收费全文 | 287篇 |
免费 | 10篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 72篇 |
金属工艺 | 1篇 |
机械仪表 | 5篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 2篇 |
轻工业 | 38篇 |
水利工程 | 1篇 |
无线电 | 40篇 |
一般工业技术 | 39篇 |
冶金工业 | 47篇 |
原子能技术 | 2篇 |
自动化技术 | 35篇 |
出版年
2022年 | 4篇 |
2021年 | 2篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 2篇 |
2015年 | 10篇 |
2014年 | 2篇 |
2013年 | 17篇 |
2012年 | 8篇 |
2011年 | 11篇 |
2010年 | 14篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 10篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 9篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1963年 | 2篇 |
1927年 | 3篇 |
1916年 | 2篇 |
1913年 | 2篇 |
排序方式: 共有297条查询结果,搜索用时 15 毫秒
11.
Bjrn Gottfried 《Journal of Visual Languages and Computing》2008,19(3):321-342
In a variety of dynamical systems, formations of motion patterns occur. Observing colonies of animals, for instance, for the scientist it is not only of interest which kinds of formations these animals show, but also how they altogether move around. In order to analyse motion patterns for the purpose of making predictions, to describe the behaviour of systems, or to index databases of moving objects, methods are required for dealing with them. This becomes increasingly important since a number of technologies have been devised which allow objects precisely to get traced. However, the indeterminacy of spatial information in real world environments also requires techniques to approximate reasoning, for example, in order to compensate for small and unimportant distinctions which are due to noisy measurements. As a consequence, precise as well as coarse motion patterns have to be dealt with.A set of 16 atomic motion patterns is proposed. On the one hand, a relation algebra is defined on them. On the other hand, these 16 relations form the basis of a visual language using which motion patterns can easily be dealt with in a diagrammatic way. The relations are coarse but crisp and they allow imprecise knowledge about motion patterns to be dealt with, while their diagrammatic realisation also allow precise patterns to get handled. While almost all approaches consider motion patterns along arbitrary time intervals, this paper in particular focuses on short-term motion patterns as we permanently observe them in our everyday life.The bottom line of the current work, however, is yet more general. While it has been widely argued that it makes sense to use both sentential and diagrammatic representations in order to represent different things in the same system adequately (and hence differently), we argue that it makes even sense to represent the same things differently in order to grasp different aspects of one and the same object of interest from different viewpoints. We demonstrate this by providing both a sentential and a diagrammatic representation for the purpose of grasping different aspects of motion patterns. It shows that both representations complement each other. 相似文献
12.
Gottfried Zimmermann Gregg Vanderheiden 《Universal Access in the Information Society》2008,7(1-2):117-128
Accessible design principles should permeate virtually all phases of the application development cycle, using existing “best practices of software engineering” for accessibility purposes. This paper proposes a methodology for accessible design and testing that includes proven tools of software engineering, namely use cases and scenarios, to capture functional requirements. Guidelines developed through user testing and heuristics are made real using personas to exemplify accessibility requirements, reflecting a diversity of user capabilities and use contexts. For implementation and testing, test cases containing accessibility checkpoints are generated, based on the guidelines. Complementary to this methodology, expert reviews and user testing should be conducted for evaluation of the developed products and further refinement of the development process. 相似文献
13.
Gottfried Spicher und Reinhard Schröder 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1979,168(3):188-192
Zusammenfassung Es wurden Ermittlungen über das Vitaminbedürfnis der an der Sauerteiggdrung beteiligten Milchsäurebakterien der UntergattungenThermobacterium, Streptobacterium andBetabacterium angestellt.Von den überprüften Sauerteigbakterien waren 54 Stämme aus sog. Reinzuchtsauerteigen und 49 Stämme aus Sauerteigen isoliert worden. Alle Sauerteigbakterien erwiesen sich biotin-, vitamin B6-, vitamin B12-, pyridoxamin- und pyridoxalautotroph. Ohne Ausnahme besteht bei den Sauerteigbakterien ein Bedürfnis an Pantothensäure und Nicotinsäure. Die Bedürftigkeit der Sauerteigbakterien an Folsäure, Vitamin B2 und Vitamin B1 ist von Art zu Art wechselnd.Das Vitaminbedürfnis der verschiedenen Gruppen von Sauerteigbakterien steht weitgehend in Übereinstimmung mit dem Bedürfnis der jeweils zum Vergleich herangezogenen Milchsäurebakterien definierter Art. Die Befunde geben somit eine Bestätigung der anhand des Zuckerspektrums vorgenommenen Zuordnung der Sauerteigbakterien zu den ArtenLactobacillus aeidophilus, L. casei, L. plantarum, L. fareiminis, L. brevis, L. brevis var. lindneri, L. fermentum undL. fructivorans.
Nr. 4470 der Veröffentlichungen der Bundesforschungsanstalt für Getreide- und Kartoffelverarbeitung, Detmold
Diese Untersuchungen wurden ermöglicht durch eine finanzielle Förderung seitens des Bundesministeriums für Forschung und Technologie im Rahmen des Programmes Biologie und Technik 相似文献
The microflora of sourdoughV. Communication: The vitamin requirement of lactic acid bacteria (Genus lactobacillus Beijerinck) of sourdough starter and sourdough
Summary Research was carried out on the vitamin requirements of lactic acid bacteria of the subgeneraThermobacterium, Streptobacterium andBetabacterium, which have a part in the sourdough fermentation. Of the investigated sourdough bacteria 54 strains were isolated from the Reinzuchtsauer (a starter culture) and 49 strains from sourdough. All sourdough bacteria were biotin-, vitamin B6-, vitamin B12-, pyridoxamine-and pyridoxal-autotroph. All sourdough bacteria showed a requirement for pantothenic acid and nicotinic acid. The requirement of sourdough bacteria for folic acid, vitamin B2 and vitamin B1 varied from species to species. The vitamin requirements of the different species of sourdough bacteria mostly agree with the requirements of reference strains of lactic acid bacteria (ATCC-strains, DSM-strains) with which they were compared. The results are therefore a confirmation for having assigned the sourdough bacteria from their sugar fermentation reactions to the speciesLactobacillus acidophilus, L. casei, L. plantarum, L. farciminis, L. brevis, L. fermentum, L. fructivorans andL. brevis var. lindneri.
Nr. 4470 der Veröffentlichungen der Bundesforschungsanstalt für Getreide- und Kartoffelverarbeitung, Detmold
Diese Untersuchungen wurden ermöglicht durch eine finanzielle Förderung seitens des Bundesministeriums für Forschung und Technologie im Rahmen des Programmes Biologie und Technik 相似文献
14.
Marko Jovanovi? Richard Tyldesley-Worster Gottfried Pohlentz Jasna Peter-Katalini? 《International journal of molecular sciences》2014,15(4):6527-6543
Human milk oligosaccharides (HMO) represent the bioactive components of human milk, influencing the infant’s gastrointestinal microflora and immune system. Structurally, they represent a highly complex class of analyte, where the main core oligosaccharide structures are built from galactose and N-acetylglucosamine, linked by 1–3 or 1–4 glycosidic linkages and potentially modified with fucose and sialic acid residues. The core structures can be linear or branched. Additional structural complexity in samples can be induced by endogenous exoglycosidase activity or chemical procedures during the sample preparation. Here, we show that using matrix-assisted laser desorption/ionization (MALDI) quadrupole-time-of-flight (Q-TOF) collision-induced dissociation (CID) as a fast screening method, diagnostic structural information about single oligosaccharide components present in a complex mixture can be obtained. According to sequencing data on 14 out of 22 parent ions detected in a single high molecular weight oligosaccharide chromatographic fraction, 20 different oligosaccharide structure types, corresponding to over 30 isomeric oligosaccharide structures and over 100 possible HMO isomers when biosynthetic linkage variations were taken into account, were postulated. For MS/MS data analysis, we used the de novo sequencing approach using diagnostic ion analysis on reduced oligosaccharides by following known biosynthetic rules. Using this approach, de novo characterization has been achieved also for the structures, which could not have been predicted. 相似文献
15.
16.
Terry L. Friesz Jack Weiss Joel Gottfried 《Civil Engineering and Environmental Systems》2013,30(2):63-68
This paper reviews the concept of a diagonalization algorithm for use in solving traffic network equilibrium problems for which the arc cost and/or the origin-destination travel demand functions are asymmetric. Such functions are known to occur in realistic settings involving multiple modes or users. The computational performance of this algorithm for different degrees of travel demand asymmetry is then explored by a detailed numerical experiment since no previous results of this type have been reported. It is found that, through the use of progressive stopping tolerances, the impact of high degrees of travel demand function asymmetry on the computational burden associated with finding a traffic network equilibrium may be mitigated; in effect equilibrium problems with high degrees of demand asymmetry are little more difficult to solve than perfectly symmetric problems. 相似文献
17.
Wolfram Witte Daniel Abou‐Ras Karsten Albe Gottfried H. Bauer Frank Bertram Christian Boit Rudolf Brüggemann Jürgen Christen Jens Dietrich Axel Eicke Dimitrios Hariskos Matthias Maiberg Roland Mainz Max Meessen Mathias Müller Oliver Neumann Thomas Orgis Stefan Paetel Johan Pohl Humberto Rodriguez‐Alvarez Roland Scheer Hans‐Werner Schock Thomas Unold Alfons Weber Michael Powalla 《Progress in Photovoltaics: Research and Applications》2015,23(6):717-733
The gallium gradient in Cu(In,Ga)Se2 (CIGS) layers, which forms during the two industrially relevant deposition routes, the sequential and co‐evaporation processes, plays a key role in the device performance of CIGS thin‐film modules. In this contribution, we present a comprehensive study on the formation, nature, and consequences of gallium gradients in CIGS solar cells. The formation of gallium gradients is analyzed in real time during a rapid selenization process by in situ X‐ray measurements. In addition, the gallium grading of a CIGS layer grown with an in‐line co‐evaporation process is analyzed by means of depth profiling with mass spectrometry. This gallium gradient of a real solar cell served as input data for device simulations. Depth‐dependent occurrence of lateral inhomogeneities on the µm scale in CIGS deposited by the co‐evaporation process was investigated by highly spatially resolved luminescence measurements on etched CIGS samples, which revealed a dependence of the optical bandgap, the quasi‐Fermi level splitting, transition levels, and the vertical gallium gradient. Transmission electron microscopy analyses of CIGS cross‐sections point to a difference in gallium content in the near surface region of neighboring grains. Migration barriers for a copper‐vacancy‐mediated indium and gallium diffusion in CuInSe2 and CuGaSe2 were calculated using density functional theory. The migration barrier for the InCu antisite in CuGaSe2 is significantly lower compared with the GaCu antisite in CuInSe2, which is in accordance with the experimentally observed Ga gradients in CIGS layers grown by co‐evaporation and selenization processes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
18.
Mohammed Al-Duais Lars Müller Volker Böhm Gottfried Jetschke 《European Food Research and Technology》2009,228(5):813-821
In the framework of standardisation of new healthy food sources, this paper aimed to study the total phenolics and the antioxidant
power of Cyphostemma digitatum (Vitaceae) in water and ethanol extracts, using 96-well micro plates with BMG FLUOstar Optima micro plate reader. Total phenolics
by Folin–Ciocalteu method in the water extracts were significantly lower after processing, decreasing from 1.41 ± 0.06 g GAE/100 g
in the raw leaves to 0.80 ± 0.08 g GAE/100 g in the processed sample; the ethanol extract revealed the same trend with higher
values, decreasing from 1.95 ± 0.03 to 1.56 ± 0.12 g GAE/100 g. The antioxidant capacity was elucidated by four methods: TEAC,
DPPH, FRAP and ORAC. No or very weak correlations were found between antioxidant assays and total phenolics; this confirms
that the antioxidant capacity could be attributed to other molecules. The ORAC assay proved to be more powerful than the other
assays; it showed 103.3 ± 2.5 mmol/100 g Trolox equivalents in the raw leaves ethanol extract and 91.9 ± 3.0 mmol/100 g in
the processed sample. ORAC assay showed the opposite for the water extract where the antioxidant capacity increased from 16.7 ± 0.2
to 41.7 ± 2.7 mmol/100 g Trolox equivalents after processing, which could be attributed to new water-soluble compounds generated
in the consumed form. 相似文献
19.
Júlio Santos-Terra Iohanna Deckmann Giovanna Carello-Collar Gustavo Della-Flora Nunes Guilherme Bauer-Negrini Gustavo Brum Schwingel Mellanie Fontes-Dutra Rudimar Riesgo Carmem Gottfried 《International journal of molecular sciences》2022,23(8)
Autism spectrum disorder (ASD) is a prevalent neurodevelopmental disorder characterized by several alterations, including disorganized brain cytoarchitecture and excitatory/inhibitory (E/I) imbalance. We aimed to analyze aspects associated with the inhibitory components in ASD, using bioinformatics to develop notions about embryonic life and tissue analysis for postnatal life. We analyzed microarray and RNAseq datasets of embryos from different ASD models, demonstrating that regions involved in neuronal development are affected. We evaluated the effect of prenatal treatment with resveratrol (RSV) on the neuronal organization and quantity of parvalbumin-positive (PV+), somatostatin-positive (SOM+), and calbindin-positive (CB+) GABAergic interneurons, besides the levels of synaptic proteins and GABA receptors in the medial prefrontal cortex (mPFC) and hippocampus (HC) of the ASD model induced by valproic acid (VPA). VPA increased the total number of neurons in the mPFC, while it reduced the number of SOM+ neurons, as well as the proportion of SOM+, PV+, and CB+ neurons (subregion-specific manner), with preventive effects of RSV. In summary, metabolic alterations or gene expression impairments could be induced by VPA, leading to extensive damage in the late developmental stages. By contrast, due to its antioxidant, neuroprotective, and opposite action on histone properties, RSV may avoid damages induced by VPA. 相似文献
20.
Our earlier investigations of fatigue behavior in PBT-GF and SAN-GF with different fiber lengths have shown that fatigue crack propagation (FCP) can be described in terms of elastic-plastic fracture mechanics. In this work it is shown that the influence of structural material parameters on the resistance to FCP correlates with the extent of energy dissipation at the crack tip. With increasing fiber length, the zone of energy dissipation is increased. By means of microscopic investigations, the prevailing damage in the zone of energy dissipation is identified as micro cracks in the matrix. 相似文献