全文获取类型
收费全文 | 1418篇 |
免费 | 57篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 29篇 |
综合类 | 4篇 |
化学工业 | 404篇 |
金属工艺 | 31篇 |
机械仪表 | 29篇 |
建筑科学 | 70篇 |
矿业工程 | 5篇 |
能源动力 | 24篇 |
轻工业 | 215篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 98篇 |
一般工业技术 | 226篇 |
冶金工业 | 209篇 |
原子能技术 | 7篇 |
自动化技术 | 122篇 |
出版年
2022年 | 10篇 |
2021年 | 24篇 |
2020年 | 13篇 |
2019年 | 13篇 |
2018年 | 25篇 |
2017年 | 21篇 |
2016年 | 27篇 |
2015年 | 29篇 |
2014年 | 41篇 |
2013年 | 77篇 |
2012年 | 52篇 |
2011年 | 64篇 |
2010年 | 32篇 |
2009年 | 47篇 |
2008年 | 45篇 |
2007年 | 55篇 |
2006年 | 58篇 |
2005年 | 28篇 |
2004年 | 27篇 |
2003年 | 27篇 |
2002年 | 34篇 |
2001年 | 25篇 |
2000年 | 18篇 |
1999年 | 24篇 |
1998年 | 56篇 |
1997年 | 28篇 |
1996年 | 22篇 |
1995年 | 25篇 |
1994年 | 20篇 |
1993年 | 26篇 |
1992年 | 21篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 12篇 |
1988年 | 18篇 |
1987年 | 19篇 |
1986年 | 16篇 |
1985年 | 14篇 |
1984年 | 12篇 |
1983年 | 16篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 23篇 |
1979年 | 12篇 |
1978年 | 12篇 |
1977年 | 10篇 |
1976年 | 22篇 |
1975年 | 16篇 |
1974年 | 13篇 |
1972年 | 13篇 |
排序方式: 共有1476条查询结果,搜索用时 366 毫秒
121.
Natalia Schiefermeier-Mach Violetta Moresco Stephan Geley Lea Heinrich Lukas Lechner Heidi Oberhauser Susanne Perkhofer 《International journal of molecular sciences》2021,22(11)
Inhaled Aspergillus fumigatus spores can be internalized by alveolar type II cells. Cell lines stably expressing fluorescently labeled components of endocytic pathway enable investigations of intracellular organization during conidia internalization and measurement of the process kinetics. The goal of this report was to evaluate the methodological appliance of cell lines for studying fungal conidia internalization. We have generated A549 cell lines stably expressing fluorescently labeled actin (LifeAct-mRuby2) and late endosomal protein (LAMP1-NeonGreen) following an evaluation of cell-pathogen interactions in live and fixed cells. Our data show that the LAMP1-NeonGreen cell line can be used to visualize conidia co-localization with LAMP1 in live and fixed cells. However, caution is necessary when using LifeAct-mRuby2-cell lines as it may affect the conidia internalization dynamics. 相似文献
122.
R Keul PC Heinrich G Müller-newen K Muller P Woo 《Canadian Metallurgical Quarterly》1998,10(9):729-734
Investigation of the agonist and two antagonists to interleukin 6 (IL-6) and their possible role in the pathogenesis of different sub-groups of juvenile chronic arthritis (JCA). Sera of 54 patients and 10 age-matched controls were tested: 20 with pauci-articular JCA, 12 with polyarticular JCA, and 22 systemic JCA. Interleukin 6, soluble interleukin 6 receptor (agonist), soluble gp130 and autoantibodies to IL-6 (antagonist to IL-6) were measured, as well as C-reactive protein as an indicator of disease activity. In addition, during fever two systemic JCA patients were analysed longitudinally for these parameters. There was a significant increase in soluble IL-6 receptor (sIL-6R) concentrations. No difference in the levels of soluble gp130 and autoantibodies to IL-6 in the systemic JCA group was found. In two patients the fever curves corresponded to the IL-6 levels measured. sIL-6R serum concentrations also showed a tendency to follow the fever. The authors have shown that in systemic JCA, the levels of sIL-6R, agonist of IL-6, were increased significantly compared to the other groups, while levels of antagonists to IL-6 were not changed in the face of increased levels of IL-6 in systemic JCA. These results suggest an imbalance of IL-6 homeostasis. 相似文献
123.
124.
It is theoretically analysed whether the structural design of ATP-producing pathways, in particular the design of glycolysis, may be explained by optimization principles. On the basis of kinetic and thermodynamic principles conclusions are derived concerning the stoichiometry of these pathways in states of high ATP production rates. One of the extensions to previous investigations is that the concentrations of the adenine nucleotides are taken into account as variable quantities. This necessitates the consideration of an interaction of the ATP-producing system I with an external ATP-consuming system II. A great variety of pathways is studied which differ in the number and location of ATP-consuming reactions, ATP-producing reactions and reactions involving inorganic phosphate. The corresponding number of possible pathways may be calculated in an explicit manner as a function of the number of those reactions which do not couple to ATP or inorganic phosphate. The kinetics of the individual reactions are described by linear or bilinear functions of reactant concentrations and all rate equations are expressed in terms of equilibrium constants and characteristic times. A thermo-dynamical analysis of the two coupled systems yields upper and lower limits for the concentration of ATP and an explicit expression for the maximal difference between the number of ATP-producing and ATP-consuming reactions of system I. The following results of the optimization are obtained. (i) The ATP production rate always increases if the ATP-producing reactions as well as those reactions characterized by an uptake of inorganic phosphate are shifted as far as possible towards the end of system I. (ii) Explicit conditions for the optimal location of the ATP-consuming reactions are presented. The results are discussed in the context of characteristic times as well as in terms of enzyme kinetic parameters. (iii) For two sets of characteristic times the resulting stoichiometries and their corresponding steady-state fluxes are investigated in detail. One of these stoichiometries shows a close correspondence to contemporary standard glycolysis. (iv) It is shown that most possible pathways result in a very low steady-state flux, that is, the optimal stoichiometry is characterized by a significant selective advantage. (v) The standard free energy profile of a pathway with an optimal stoichiometry is discussed. It differs significantly from the free energy profiles of nonoptimized pathways. 相似文献
125.
鼓肚变形及因变形引起的中心线偏析是影响板坯质量的重要因素.法国冶金部和一些企业组织了优化钢铁生产的项目,采用数值方法研究和优化连铸工艺.介绍了巴黎高等矿业学校在连铸过程数值仿真方面的研究成果. 相似文献
126.
Zusammenfassung In diesem Beitrag wird ein Überblic über die Probleme vermittelt, die sich bei der Konfiguration und dem Betrieb eines flexiblen Fertigungssystems stellen. Die zur Behandlung der wichtigsten Problemtypen verfügbaren Modellierungsansätze werden systematisch beschrieben und auf ihren möglichen Einsatz zur Entscheidungsunterstützung für die betriebliche Praxis hin untersucht. 相似文献
127.
Prof. Dr. Hans Ulrich Buhl Dr. Bernd Heinrich Dr. Werner Steck Veronica Winkler 《WIRTSCHAFTSINFORMATIK》2004,46(6):427-438
The article describes and discusses requirements as well as the business concept to generate financially optimized and individualized advisory suggestions for private customers in the financial industry. On this basis we presently design business and technical components of an advisory system. Within the research cooperation for situation, individualization and personalization (FORSIP) the system is prototypically implemented in the context of retirement planning. In addition we discuss possibilities for a customer-friendly visualization of investment risk and their technically implementation within the prototype. 相似文献
128.
129.
130.
Due to the loss of range information, projections as input data for a 3-D object recognition algorithm are expected to increase the computational complexity. In this work, however, we demonstrate that this deficiency carries potential for complexity reduction of major vision problems. We show that projections provide a reduction of feature dimensions, and lead to structures exhibiting simple combinatorial properties. The theoretical framework is embedded in a probabilistic setting which deals with uncertainties and variations of observed features. In statistics marginal densities and the assumption of independency prove to be the key tools when one encounters projections. The examples discussed in this paper include feature matching, pose estimation as well as classification of 3-D objects. The final experimental evaluation demonstrates the practical importance of the marginalization concept and independency assumptions. 相似文献