全文获取类型
收费全文 | 283篇 |
免费 | 16篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 60篇 |
金属工艺 | 3篇 |
机械仪表 | 3篇 |
建筑科学 | 18篇 |
矿业工程 | 5篇 |
能源动力 | 17篇 |
轻工业 | 70篇 |
水利工程 | 3篇 |
无线电 | 16篇 |
一般工业技术 | 40篇 |
冶金工业 | 18篇 |
原子能技术 | 4篇 |
自动化技术 | 40篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 6篇 |
2014年 | 13篇 |
2013年 | 22篇 |
2012年 | 20篇 |
2011年 | 21篇 |
2010年 | 12篇 |
2009年 | 21篇 |
2008年 | 13篇 |
2007年 | 26篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 5篇 |
2003年 | 10篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 1篇 |
1995年 | 9篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有301条查询结果,搜索用时 15 毫秒
71.
M. Schröder K. Kailasam S. Rudi M. Richter A. Thomas R. Schomäcker M. Schwarze 《International Journal of Hydrogen Energy》2014
Sacrificial hydrogen evolution was studied with sol–gel prepared carbon nitride photocatalysts loaded in-situ with platinum in a photocatalytic setup with defined geometry and a solar simulator as light source. Reaction conditions (e.g. photocatalyst concentration, triethanolamine concentration, amount of Pt precursor, water quality, etc.), and catalyst properties (e.g. BET surface area) were varied to optimize the catalysts for hydrogen evolution. We found that most of the parameters strongly influence the in-situ co-catalyst loading. The optimum platinum loading is between 0.03 and 0.09 wt%, which is less than 5% of the initial amount of platinum. A long term stability test was conducted showing a stable hydrogen evolution rate for more than 10 days indicating a stable catalyst under applied reaction conditions. We found that a change in the BET surface area affects the photocatalytic activity rather than the experimental conditions. 相似文献
72.
数值模拟与极限平衡方法在复杂边坡优化中的应用研究 总被引:1,自引:0,他引:1
露天矿山最终边坡角的设计是否合理,将对边坡的稳定性、矿山的生产安全和经济效益产生重大影响。结合一露天矿山的二期扩采需要,采用大型非线性固-流耦合FLAC数值模拟方法进行了边坡多种方案的应力场、破坏场、监测点位移、位移速度变化趋势等多种指标分析,并采用传统的极限平衡分析方法对数值模拟分析推荐的边坡设计方案进行稳定性计算, 最后,综合分析得出最佳方案。研究表明,数值模拟方法和极限平衡方法相结合是进行复杂边坡优化的一条合理有效途径,该方法可为矿山提出安全、经济、切实可行的边坡设计方案。 相似文献
73.
Yuming Chen Rudi Kulenovic Rainer Mertz 《International Journal of Thermal Sciences》2009,48(2):234-242
Numerical simulations have been carried out for the transient formation of Taylor bubbles in a nozzle/tube co-flow arrangement by solving the unsteady, incompressible Navier–Stokes equations. A level set method was used to track the two-phase interface. The calculated bubble size, shape, liquid film thickness, bubble length, drift velocity, pressure drop and flow fields of Taylor flow agree well with the literature data. For a given nozzle/tube configuration, the formation of Taylor bubbles is found to be mainly dependent on the relative magnitude of gas and liquid superficial velocity. However, even under the same liquid and gas superficial velocities, the change of nozzle geometry alone can drastically change the size of Taylor bubbles and the pressure drop behavior inside a given capillary. This indicates that the widely used flow pattern map presented in terms of liquid and gas superficial velocities is not unique. 相似文献
74.
75.
76.
77.
Jürgen W. A. Sijbesma Aren van Waarde Lars Stegger Rudi A. J. O. Dierckx Hendrikus H. Boersma Riemer H. J. A. Slart 《International journal of molecular sciences》2021,22(6)
Background: High protein (HP) diets have been proposed to reduce body weight in humans. The diets are known to alter energy metabolism, which can affect the quality of [18F]FDG PET heart images. In this preclinical study, we therefore explore the impact of a prolonged HP diet on myocardial [18F]FDG uptake. Methods: C57BL/6J (Black six (Bl6)) and apolipoprotein E-deficient (apoE−/−) mice were fed chow, a HP diet, or a low protein (LP) diet for 12 weeks. At baseline and after treatment, the animals were injected with 33.0 MBq of [18F]FDG and a 30 min PET/CT scan was made. Myocardial volume and [18F]FDG uptake were quantified using PET and the % of body fat was calculated from CT. Results: Myocardial [18F]FDG uptake was similar for all diets at the follow-up scan but an increase between baseline and follow-up scans was noticed in the LP groups. Myocardial volume was significantly smaller in the C57BL HP group compared to the other Bl6 groups. Body weight increased less in the two HP groups compared to the chow and LP groups. Body fat percentage was significantly higher in the LP groups. This effect was stronger in C57BL mice (28.7%) compared to apoE−/− mice (15.1%). Conclusions: Myocardial uptake of [18F]FDG in mice is not affected by increased protein intake but [18F]FDG uptake increases when the amount of protein is lowered. A lower body weight and percentage of body fat were noticed when applying a HP diet. 相似文献
78.
Denise van Uden Thomas Koudstaal Jennifer A. C. van Hulst Ingrid M. Bergen Chelsea Gootjes Nicholas W. Morrell Geert van Loo Jan H. von der Thüsen Thierry P. P. van den Bosch Maria-Rosa Ghigna Frdric Perros David Montani Mirjam Kool Karin A. Boomars Rudi W. Hendriks 《International journal of molecular sciences》2021,22(4)
The pathogenesis of idiopathic pulmonary arterial hypertension (IPAH) is not fully understood, but evidence is accumulating that immune dysfunction plays a significant role. We previously reported that 31-week-old Tnfaip3DNGR1-KO mice develop pulmonary hypertension (PH) symptoms. These mice harbor a targeted deletion of the TNFα-induced protein-3 (Tnfaip3) gene, encoding the NF-κB regulatory protein A20, specifically in type I conventional dendritic cells (cDC1s). Here, we studied the involvement of dendritic cells (DCs) in PH in more detail. We found various immune cells, including DCs, in the hearts of Tnfaip3DNGR1-KO mice, particularly in the right ventricle (RV). Secondly, in young Tnfaip3DNGR1-KO mice, innate immune activation through airway exposure to toll-like receptor ligands essentially did not result in elevated RV pressures, although we did observe significant RV hypertrophy. Thirdly, PH symptoms in Tnfaip3DNGR1-KO mice were not enhanced by concomitant mutation of bone morphogenetic protein receptor type 2 (Bmpr2), which is the most affected gene in PAH patients. Finally, in human IPAH lung tissue we found co-localization of DCs and CD8+ T cells, representing the main cell type activated by cDC1s. Taken together, these findings support a unique role of cDC1s in PAH pathogenesis, independent of general immune activation or a mutation in the Bmpr2 gene. 相似文献
79.
Aspects of high hydrostatic pressure food processing: Perspectives on technology and food safety 总被引:1,自引:0,他引:1
Kemal Aganovic Christian Hertel Rudi. F. Vogel Reimar Johne Oliver Schlüter Uwe Schwarzenbolz Henry Jäger Thomas Holzhauser Johannes Bergmair Angelika Roth Robert Sevenich Niels Bandick Sabine E. Kulling Dietrich Knorr Karl-Heinz Engel Volker Heinz 《Comprehensive Reviews in Food Science and Food Safety》2021,20(4):3225-3266
The last two decades saw a steady increase of high hydrostatic pressure (HHP) used for treatment of foods. Although the science of biomaterials exposed to high pressure started more than a century ago, there still seem to be a number of unanswered questions regarding safety of foods processed using HHP. This review gives an overview on historical development and fundamental aspects of HHP, as well as on potential risks associated with HHP food applications based on available literature. Beside the combination of pressure and temperature, as major factors impacting inactivation of vegetative bacterial cells, bacterial endospores, viruses, and parasites, factors, such as food matrix, water content, presence of dissolved substances, and pH value, also have significant influence on their inactivation by pressure. As a result, pressure treatment of foods should be considered for specific food groups and in accordance with their specific chemical and physical properties. The pressure necessary for inactivation of viruses is in many instances slightly lower than that for vegetative bacterial cells; however, data for food relevant human virus types are missing due to the lack of methods for determining their infectivity. Parasites can be inactivated by comparatively lower pressure than vegetative bacterial cells. The degrees to which chemical reactions progress under pressure treatments are different to those of conventional thermal processes, for example, HHP leads to lower amounts of acrylamide and furan. Additionally, the formation of new unknown or unexpected substances has not yet been observed. To date, no safety-relevant chemical changes have been described for foods treated by HHP. Based on existing sensitization to non-HHP-treated food, the allergenic potential of HHP-treated food is more likely to be equivalent to untreated food. Initial findings on changes in packaging materials under HHP have not yet been adequately supported by scientific data. 相似文献
80.
Domain models can be constructed more easily and made more robust by reusing ontologies in a well-defined way. In this paper the KARO approach is introduced which provides various means of retrieving and adapting components of an ontology as part of a domain model construction process. KARO is based on the knowledge-processing component LILOG-KR provided by the LILOG text-understanding system. Above all, the notion of classification is applied for the retrieval of relevant categories. The upper structure of LILOG-KB serves as an exemplary ontology. By integrating KARO into the Model-based and Incremental Knowledge Engineering Environment (MIKE) the reuse of a predefined ontology can be integrated into the development process of expert systems in a systematic way. 相似文献