全文获取类型
收费全文 | 1063篇 |
免费 | 70篇 |
专业分类
电工技术 | 14篇 |
综合类 | 1篇 |
化学工业 | 283篇 |
金属工艺 | 29篇 |
机械仪表 | 17篇 |
建筑科学 | 32篇 |
矿业工程 | 1篇 |
能源动力 | 73篇 |
轻工业 | 121篇 |
水利工程 | 9篇 |
石油天然气 | 1篇 |
无线电 | 79篇 |
一般工业技术 | 185篇 |
冶金工业 | 91篇 |
原子能技术 | 7篇 |
自动化技术 | 190篇 |
出版年
2023年 | 5篇 |
2022年 | 37篇 |
2021年 | 52篇 |
2020年 | 27篇 |
2019年 | 35篇 |
2018年 | 36篇 |
2017年 | 49篇 |
2016年 | 42篇 |
2015年 | 29篇 |
2014年 | 63篇 |
2013年 | 75篇 |
2012年 | 50篇 |
2011年 | 86篇 |
2010年 | 56篇 |
2009年 | 59篇 |
2008年 | 43篇 |
2007年 | 46篇 |
2006年 | 37篇 |
2005年 | 27篇 |
2004年 | 24篇 |
2003年 | 23篇 |
2002年 | 22篇 |
2001年 | 13篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 18篇 |
1997年 | 12篇 |
1996年 | 13篇 |
1995年 | 4篇 |
1994年 | 11篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1969年 | 4篇 |
排序方式: 共有1133条查询结果,搜索用时 484 毫秒
31.
32.
Valentina Medri Francesca Servadei Riccardo Bendoni Annalisa Natali Murri Angelo Vaccari Elena Landi 《Journal of the European Ceramic Society》2019,39(7):2453-2462
Cold Sintering Process (CSP) was applied on commercial nanopowders to produce nanostructured TiO2 anatase with nano-to-macro porosity. Nanoporous TiO2 based materials were obtained by applying CSP at 150 °C and pressures up to 500 MPa on three TiO2 nanopowders with different specific surface area (s.s.a. = 50, 90 and 370 m2/g), using water as transient aqueous environment. Although TiO2 is insoluble in water, a density of 68% and s.s.a. = 117 m2/g were achieved from the powder with the highest specific surface area. A post annealing process at 500 °C increased the density up to 73% with a s.s.a. = 59 m2/g, and the crystallites dimensions passed from 110 Å in the powder to 130 Å in CSP material and 172 Å after post annealing. Finally, macroporosity was produced by using thermoplastic polymer beads as sacrificial templates within TiO2 nanopowder during CSP, followed by a debonding at 500 °C. 相似文献
33.
34.
Angelo Anelli Sandra Santa-Cruz Marco Vona Nicola Tarque Michelangelo Laterza 《Structure and Infrastructure Engineering》2019,15(2):137-151
Different methods and procedures have been developed to define prioritisation strategies of retrofit interventions aimed at reducing the seismic risk of school buildings on a large territorial scale. However, these approaches fail to demonstrate how risk analysis has been used successfully to quantitatively assess and select the optimal risk management decision. This article proposes innovative and useful metrics to measure the potential costs and benefits related to the prioritisation of retrofit intervention and the resilience of the analysed school system by directly integrating engineering, organisational, socio-economic and political aspects in the realm of seismic resilience assessment. Based on probabilistic risk assessments considering the new vulnerability of the prioritised school buildings, these measures could predict the expected economic and functional losses associated with a disastrous seismic event, as well as the possible post-disaster recovery of the system. In order to help decision-makers in selecting the optimal mitigation strategy with a multidisciplinary and multidimensional perspective, different political scenarios, the relative prioritisations of interventions and their intervention options are also defined. The proposed framework is demonstrated in a complex case study of 1,825 public schools in the Lima metropolitan area, Peru. Policymakers, planners and engineering professionals could benefit from results. 相似文献
35.
36.
37.
Accurate measurement of institutional research productivity should account for the real contribution of the research staff to the output produced in collaboration with other organizations. In the framework of bibliometric measurement, this implies accounting for both the number of co-authors and each individual’s real contribution to scientific publications. Common practice in the life sciences is to indicate such contribution through the order of author names in the byline. In this work, we measure the distortion introduced to university-level bibliometric productivity rankings when the number of co-authors or their position in the byline is ignored. The field of observation consists of all Italian universities active in the life sciences (Biology and Medicine). The analysis is based on the research output of the university staff over the period 2004–2008. Based on the results, we recommend against the use of bibliometric indicators that ignore co-authorship and real contribution of each author to research outputs. 相似文献
38.
39.
Cristina S. Borba Joo D. Latini Matheus T. Baumgartner Luiz C. Gomes Angelo A. Agostinho 《河流研究与利用》2019,35(4):386-395
The building of adduction channels (penstocks) that conduct water from reservoirs to turbines, which are located kilometres from the dam, is becoming common, optimizing the electricity generation in small dams. This design creates a river stretch with reduced discharge between the dam and the powerhouse. This study evaluates the short‐term impacts of the below‐dam decrease in river flow on fish assemblages. Samples were collected in the reduced flow stretch of the Castro Alves Hydropower Plant (Antas River, Rio Grande do Sul, Brazil) before the reservoir started operating (January 2008; mean discharge of 103.7 m3/s) and immediately after operation began (March 2008; mean discharge of 12.4 m3/s). Sampling was conducted in distinct habitats of the reduced flow stretch (slow waters—gillnets, sand beaches—seining nets, structured littoral—electrofishing, and fast waters—cast nets) with a strongly standardized effort. The attributes of the fish assemblages were not negatively affected by the flow reduction in any habitat sampled. However, distinct changes in the spatial structure were observed considering the different types of habitat predominantly used by the species, which represents an entire reorganization of the fish assemblages in the short term. It is fundamental that these short‐term aspects be considered in the licensing of hydropower plants in addition to the long‐term changes. 相似文献
40.
Danilo Marimpietri Irma Airoldi Angelo Corso Faini Fabio Malavasi Fabio Morandi 《International journal of molecular sciences》2021,22(8)
The long-underestimated role of extracellular vesicles in cancer is now reconsidered worldwide by basic and clinical scientists, who recently highlighted novel and crucial activities of these moieties. Extracellular vesicles are now considered as king transporters of specific cargoes, including molecular components of parent cells, thus mediating a wide variety of cellular activities both in normal and neoplastic tissues. Here, we discuss the multifunctional activities and underlying mechanisms of extracellular vesicles in neuroblastoma, the most frequent common extra-cranial tumor in childhood. The ability of extracellular vesicles to cross-talk with different cells in the tumor microenvironment and to modulate an anti-tumor immune response, tumorigenesis, tumor growth, metastasis and drug resistance will be pinpointed in detail. The results obtained on the role of extracellular vesicles may represent a panel of suggestions potentially useful in practice, due to their involvement in the response to chemotherapy, and, moreover, their ability to predict resistance to standard therapies—all issues of clinical relevance. 相似文献