全文获取类型
收费全文 | 614篇 |
免费 | 28篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 167篇 |
金属工艺 | 12篇 |
机械仪表 | 16篇 |
建筑科学 | 19篇 |
能源动力 | 40篇 |
轻工业 | 70篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
无线电 | 22篇 |
一般工业技术 | 91篇 |
冶金工业 | 81篇 |
原子能技术 | 7篇 |
自动化技术 | 104篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 12篇 |
2021年 | 32篇 |
2020年 | 15篇 |
2019年 | 24篇 |
2018年 | 22篇 |
2017年 | 19篇 |
2016年 | 25篇 |
2015年 | 13篇 |
2014年 | 25篇 |
2013年 | 36篇 |
2012年 | 35篇 |
2011年 | 38篇 |
2010年 | 29篇 |
2009年 | 31篇 |
2008年 | 30篇 |
2007年 | 17篇 |
2006年 | 19篇 |
2005年 | 18篇 |
2004年 | 15篇 |
2003年 | 11篇 |
2002年 | 22篇 |
2001年 | 14篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 20篇 |
1997年 | 11篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1962年 | 1篇 |
1949年 | 1篇 |
排序方式: 共有642条查询结果,搜索用时 15 毫秒
631.
Roberto S. Carnicer Braian A. Desia Rodolfo A. Schwarz 《机械工程与自动化:英文版》2014,(10):820-827
Natural frequencies for multilayer plates are calculated by mixed finite element method. The main object of this paper is to use the mixed model for multilayer plates, analyzing each layer as an isolated plate, where the continuity of displacements is achieved by Lagrange multipliers (representing static variables). This procedure allows us to work with any model for single plate (so as to ensure the proper behavior of each layer), and the complexity of the multilayer system is avoided by ensuring the condition of displacements by the Lagrange multipliers (static variables). The plate is discretized by finite element modeling based on a primary hybrid model, where the domain is divided by quadrilateral, both for the displacement field and static variables. This mixed element for plates was implemented and several examples of vibrations have been verified successfully by the results obtained by other methods in the literature. 相似文献
632.
633.
Jacqueline A. Treat Ryan Pfeiffer Hector Barajas-Martinez Robert J. Goodrow Corina Bot Rodolfo J. Haedo Ronald Knox Jonathan M. Cordeiro 《International journal of molecular sciences》2021,22(13)
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are used for genetic models of cardiac diseases. We report an arrhythmia syndrome consisting of Early Repolarization Syndrome (ERS) and Short QT Syndrome (SQTS). The index patient (MMRL1215) developed arrhythmia-mediated syncope after electrocution and was found to carry six mutations. Functional alterations resulting from these mutations were examined in patient-derived hiPSC-CMs. Electrophysiological recordings were made in hiPSC-CMs from MMRL1215 and healthy controls. ECG analysis of the index patient showed slurring of the QRS complex and QTc = 326 ms. Action potential (AP) recordings from MMRL1215 myocytes showed slower spontaneous activity and AP duration was shorter. Field potential recordings from MMRL1215 hiPSC-CMs lack a “pseudo” QRS complex suggesting reduced inward current(s). Voltage clamp analysis of ICa showed no difference in the magnitude of current. Measurements of INa reveal a 60% reduction in INa density in MMRL1215 hiPSC-CMs. Steady inactivation and recovery of INa was unaffected. mRNA analysis revealed ANK2 and SCN5A are significantly reduced in hiPSC-CM derived from MMRL1215, consistent with electrophysiological recordings. The polygenic cause of ERS/SQTS phenotype is likely due to a loss of INa due to a mutation in PKP2 coupled with and a gain of function in IK,ATP due to a mutation in ABCC9. 相似文献
634.
Van Loo E Caputo V Nayga RM Meullenet JF Crandall PG Ricke SC 《Journal of food science》2010,75(7):S384-S397
Because of the growing consumers' interest in organic meat, consumers' (N = 976) attitude toward organic meat was evaluated. Most respondents (59%) occasionally purchased organic chicken. To determine the organic chicken consumer profile, the organic chicken consumption frequencies of different demographic groups were compared. The results show dependence on age (P= 0.039) and ethnicity (P = 0.015). Older respondents as well as respondents who identified themselves as Caucasians tended to buy organic chicken more frequently. However, many other socio-demographic factors were not correlated with organic chicken consumption: gender (P = 0.185), education (P = 0.235), household income (0.867), living with partner or not (P = 0.235), and number of children (P = 0.883). Taste was identified as the most important meat quality attribute (perceived as [very] important by 94% of the respondents). Other important meat quality criteria were: general appearance, overall health, price, nutritional value, and containing no medical residues. "Organically produced" appeared to not be that important compared with other criteria. When respondents bought organic chicken more often, the importance of most of the meat quality attributes shifted to higher levels of importance, except for the price where an adverse effect was shown. The main motivation factors to buy organic chicken were the perception that organic chicken has fewer residues (pesticides, hormones, antibiotics), is safer, and healthier. The high price for organic meats was the strongest limiting factor for organic meat purchases followed by poor availability. Approximately 41% of the non-buyers and 30% of the occasional buyers perceived organic meat as not or hardly likely to be available in their supermarket. PRACTICAL APPLICATION: This study obtained a better knowledge of consumers' attitudes and perception of organic chicken as well as the effect of various demographics on the likelihood of buying organic chicken. For marketing purposes of organic meats, it helps to know which attributes consumers perceive as important, where the consumer purchases organic chicken, and what the perceived availability of organic chicken is. Additionally, the motivation and deterrent factors are described indicating why the consumer does or does not purchase organic chicken. This information can be valuable to help promoting organic meats to the consumers. 相似文献
635.
Rodolfo Gómez 《Formal Aspects of Computing》2013,25(2):289-318
Timed automata with deadlines (TAD) are a form of timed automata that admit a more natural representation of urgent actions, with the additional advantage of avoiding the most common form of timelocks. We offer a compositional translation of a practically useful subset of TAD to timed safety automata (the well-known variant of timed automata where time progress conditions are expressed by invariants). More precisely, we translate networks of TAD to the modeling language of Uppaal, a state-of-the-art verification tool for timed automata. We also describe an implementation of this translation, which allows Uppaal to aid the design and analysis of TAD models. 相似文献
636.
637.
Jassiel V. H. Fontes Eliana Brandão da Silva Rodolfo Silva Mojtaba Maali Amiri Edgar Mendoza Harlysson W. S. Maia Irving D. Hernández 《Water and Environment Journal》2023,37(4):644-656
The Amazon basin is one of the largest hydrographic systems in the world, possessing a great diversity of natural resources in need of more sustainable water and environmental management. However, as much of what lies beneath the surface of Amazonian waters is still unexplored, underwater exploration technologies are seen as a means of research and monitoring. The present work therefore aims to answer two research questions: What are the current technologies that could be implemented for unmanned underwater research in the Amazon waters? What are the main limitations and existing alternatives for using unmanned underwater vehicles in the rivers of this region to provide more sustainable water and environment management? Our results demonstrate that remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs) are possible options in the short and long terms, respectively. The main challenges in implementing these technologies are related to the variations in hydraulic geometry, current velocities and turbidity of the rivers, as well as the preservation of the region's biodiversity. This research can be taken as a starting point for planners and decision makers seeking more sustainable underwater and environmental exploration of the Amazon river system. 相似文献
638.
Rodolfo de Andrade Schaffner Carlos Eduardo Borba Fernanda Tavares Lígia Gomes Oliveira Pedro Castaño Helton José Alves 《加拿大化工杂志》2023,101(7):3693-3709
Porous carbon materials such as activated carbons are widely used industrially for the purposes of purification, decolourization, deodorization, and gas storage, among others. Routes for the synthesis of these materials employing templates have increasingly attracted attention due to the ease of manipulating the characteristics of the final product. In the present work, a simple synthesis method was applied for the production of highly porous carbon materials using commercial sugar as the carbon source, Aerosil silica as a template, and deionized water. The synthesis procedure was as follows: (I) Gel formation; (II) carbonization of the gels; (III) removal of the silica template; (IV) activation. The materials were characterized by N2 and CO2 physisorption, Raman spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy, and thermogravimetric analysis. The aging time had an important influence on the specific area and porosity of the material, with physisorption analysis revealing a high specific area and pore volume. The activation procedures further contributed to significantly increasing the specific area (up to 1158 m2 g−1) and pore volume (up to 1.65 cm3 g−1). The X-ray diffractograms and Raman spectra identified the formation of semi-crystalline structures in the material, with the presence of a random distribution of graphite and graphene oxide, in addition to amorphous carbon. FTIR analysis showed the presence of bands corresponding to aromatic groups. The results demonstrated that it was possible to obtain materials with excellent potential for use in different industrial sectors using simple raw materials and a technique that is easy to reproduce. 相似文献
639.
Pavez Rodolfo Diaz Jaime Arango-Lopez Jeferson Ahumada Danay Mendez-Sandoval Carolina Moreira Fernando 《Neural computing & applications》2023,35(11):7913-7924
Neural Computing and Applications - Autism spectrum disorder (ASD) is a neurodevelopmental disorder defined as persistent difficulty in maturing the socialization process. Health professionals have... 相似文献
640.