全文获取类型
收费全文 | 1105篇 |
免费 | 44篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 32篇 |
综合类 | 8篇 |
化学工业 | 333篇 |
金属工艺 | 14篇 |
机械仪表 | 31篇 |
建筑科学 | 60篇 |
矿业工程 | 6篇 |
能源动力 | 21篇 |
轻工业 | 81篇 |
水利工程 | 6篇 |
无线电 | 109篇 |
一般工业技术 | 166篇 |
冶金工业 | 69篇 |
原子能技术 | 5篇 |
自动化技术 | 210篇 |
出版年
2023年 | 16篇 |
2022年 | 21篇 |
2021年 | 31篇 |
2020年 | 22篇 |
2019年 | 21篇 |
2018年 | 24篇 |
2017年 | 16篇 |
2016年 | 31篇 |
2015年 | 40篇 |
2014年 | 36篇 |
2013年 | 50篇 |
2012年 | 61篇 |
2011年 | 70篇 |
2010年 | 69篇 |
2009年 | 53篇 |
2008年 | 61篇 |
2007年 | 52篇 |
2006年 | 59篇 |
2005年 | 41篇 |
2004年 | 29篇 |
2003年 | 25篇 |
2002年 | 29篇 |
2001年 | 18篇 |
2000年 | 22篇 |
1999年 | 17篇 |
1998年 | 20篇 |
1997年 | 27篇 |
1996年 | 16篇 |
1995年 | 25篇 |
1994年 | 22篇 |
1993年 | 17篇 |
1992年 | 12篇 |
1991年 | 12篇 |
1990年 | 7篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1985年 | 5篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有1151条查询结果,搜索用时 15 毫秒
61.
Axel Pagán Josep Conde Alberto Ibarz Jordi Pagán 《Food and Bioproducts Processing》2010,88(2-3):77-82
This work studies the variation in the effluent content from the reactor in enzymatic peeling of grapefruits, to determine the loss of soluble solids, reducing sugars and galacturonic acid, the main component from the albedo of the skin to model the solid–liquid transfer in this process. Experiments to study the efficiency of the enzymatic reaction include the effect of the temperature on the kinetics of albedo degradation to find an equation relating both variables and also the activation energy of this process, its value being 36.9 kJ/mol. 相似文献
62.
63.
64.
The concept and use of a rotating chimney for compressing rotating fluidized beds is theoretically and experimentally studied. A rotating chimney is shown to drastically increase the operating flexibility of rotating fluidized beds and to allow a significant improvement of the particle bed uniformity. In particular, the rate of solids losses via the chimney can be reduced and bubbling can be suppressed by compressing the rotating particle bed. 相似文献
65.
Dipl. Wirt.-Inform. Ralf Knackstedt Dipl. Kfm. Axel Winkelmann 《WIRTSCHAFTSINFORMATIK》2006,48(1):47-59
Knowledge sharing is fundamental for innovations in the scientific community. The paper examines how the interaction of knowledge sharing is supported by online services. With respect to business information systems, a survey of online literature databases is given, providing an aggregation of various publication sources, a direct access to publications, and which are available to the public. Furthermore, special analysis services are presented which describe competitive interactions of knowledge sharing via rankings on the one hand, and cooperative interactions of knowledge sharing via co-authorship evaluation on the other. 相似文献
66.
Axel Schneider Holk Cruse Josef Schmitz 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2005,35(6):1120-1130
Starting from studies which revealed that positive feedback is found in the control system for walking in arthropods, we have constructed a new positive feedback driven joint that can be used for solving compliant motion tasks. We propose two different joint constructions each of which shows passive compliance. Based on these joints we introduce three different local positive velocity feedback (LPVF) controllers and discuss their properties in the context of motion generation in closed kinematic chains. The third circuit named undelayed dLPVF is used for the control of a compliant planar manipulator which turns a crank. Our concept is of highly decentralized nature and follows the idea of embodiment. In our case this means that a process which is controlled by LPVF controllers reveals its nature when the controllers interact with this process. 相似文献
67.
Why so many forms of acetylcholinesterase? 总被引:4,自引:0,他引:4
Legay C 《Microscopy research and technique》2000,49(1):56-72
Acetylcholinesterase is a key molecule in the control of cholinergic transmission. In the mammalian neuromuscular junction (NMJ), the efficiency of this phenomenon depends on the enzyme location, between the presynaptic site where acetylcholine is released and the postsynaptic membrane where the acetylcholine receptors are packed. Various molecular forms of the enzyme that possess the same catalytic activity are expressed. The relative amounts of these forms are tissue-specific. At the subcellular level, this panoply of forms allows the enzyme to be attached to the membrane or to the basal lamina. Analysis of the forms secreted and their position in the cytoarchitecture of the NMJ is essential to understand the functioning of this synapse. This review will consider the origin of the enzyme polymorphism and its physiological implication. 相似文献
68.
Gill Raj; Verma Chandra; Wallach Brenda; Urso Birgitte; Pitts Jim; Wollmer Axel; De Meyts Pierre; Wood Steve 《Protein engineering, design & selection : PEDS》1999,12(4):297-303
Insulin-like growth factor-1 (IGF-1) is a serum protein whichunexpectedly folds to yield two stable tertiary structures withdifferent disulphide connectivities; native IGF-1 [1861,648,4752]and IGF-1 swap [1861,647, 4852]. Here we demonstratein detail the biological properties of recombinant human nativeIGF-1 and IGF-1 swap secreted from Saccharomyces cerevisiae.IGF-1 swap had a ~30 fold loss in affinity for the IGF-1 receptoroverexpressed on BHK cells compared with native IGF-1.The parallelincrease in dose required to induce negative cooperativity togetherwith the parallel loss in mitogenicity in NIH 3T3 cells impliesthat disruption of the IGF-1 receptor binding interaction ratherthan restriction of a post-binding conformational change isresponsible for the reduction in biological activity of IGF-1swap. Interestingly, the affinity of IGF-1 swap for the insulinreceptor was ~200 fold lower than that of native IGF-1 indicatingthat the binding surface complementary to the insulin receptor(or the ability to attain it) is disturbed to a greater extentthan that to the IGF-1 receptor. A 1.0 ns high-temperature moleculardynamics study of the local energy landscape of IGF-1 swap resultedin uncoiling of the first A-region -helix and a rearrangementin the relative orientation of the A- and B-regions. The modelof IGF-1 swap is structurally homologous to the NMR structureof insulin swap and CD spectra consistent with the model arepresented. However, in the model of IGF-1 swap the C-regionhas filled the space where the first A-region -helix has uncoiledand this may be hindering interaction of Val44 with the secondinsulin receptor binding pocket. 相似文献
69.
DL Kraitchman AA Young DC Bloomgarden ZA Fayad L Dougherty VA Ferrari RC Boston L Axel 《Canadian Metallurgical Quarterly》1998,40(2):311-326
A single integrated examination using regional measurements of perfusion from contrast-enhanced MRI and three-dimensional (3D) strain from tissue-tagged MRI was developed to differentiate infarcted myocardium from adjacent tissue with functional abnormalities. Ten dogs were studied at baseline and 10 days after a 2-hour occlusion of the left anterior descending coronary artery (LAD). Strain was determined using a 3D finite element model. Two-dimensional measurements of hypoenhancing regions were highly correlated with myocardial viability (r = 0.96). Signal intensity versus time curves obtained from contrast-enhanced MRI were used for quantitative perfusion analysis. The remote and adjacent noninfarcted tissue of the dogs with LAD occlusion, as well as the infarcted tissue, exhibited abnormal deformation patterns as compared to normal dogs (positive predictive value (PPV) of strain determination of infarction = 66%). Integration of contrast-enhanced MRI results with 3D strain analysis enabled the delineation of the myocardial infarction (PPV = 100%) from functionally compromised myocardium. This integrated cardiac examination shows promise for noninvasive serial assessment of potentially jeopardized noninfarcted myocardium to study the process of infarct remodeling and expansion. 相似文献
70.
Notes that electrolytic lesions of the centrum-medianum and parafascicularis complex of the thalamus produce, in the rat, large deficits of both acquisition and retention of active-avoidance responses, especially in the 2-way shuttle-box test. The effect of such lesions on 26 male cats and 6 male and 2 female macaques was examined. It was found that lesions in the cat did not produce significant effects, either with acoustical or visual CS, during postoperative relearning. Moreover, rate of extinction was not affected. Negative results were also found in monkeys. These lesions did not modify the threshold of flinch or jump responses to electric shock in either species. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献