全文获取类型
收费全文 | 188篇 |
免费 | 33篇 |
专业分类
化学工业 | 76篇 |
金属工艺 | 1篇 |
建筑科学 | 5篇 |
能源动力 | 1篇 |
轻工业 | 57篇 |
无线电 | 20篇 |
一般工业技术 | 47篇 |
冶金工业 | 5篇 |
自动化技术 | 9篇 |
出版年
2023年 | 4篇 |
2022年 | 20篇 |
2021年 | 23篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 16篇 |
2017年 | 5篇 |
2016年 | 17篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 9篇 |
2012年 | 15篇 |
2011年 | 9篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1985年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有221条查询结果,搜索用时 10 毫秒
211.
Effects of nano-scaled particles on endothelial cell function in vitro: Studies on viability, proliferation and inflammation 总被引:4,自引:0,他引:4
Peters K Unger RE Kirkpatrick CJ Gatti AM Monari E 《Journal of materials science. Materials in medicine》2004,15(4):321-325
Recent studies give support for a connection between the presence of inorganic particles (of m and nm size) in different organs and tissues and the development of inflammatory foci, called granulomas. As the potential source of particles (e.g. porcelain dental bridges) and the location of particle detection were topographically far apart, a distribution via the blood stream appears highly probable. Thus, endothelial cells, which line the inner surface of blood vessels, would come into direct contact with these particles, making particle–endothelial interactions potentially pathogenically relevant. The objective of this study was to evaluate the effects that five different nano-scaled particles (PVC, TiO2, SiO2, Co, Ni) have on endothelial cell function and viability. Therefore, human endothelial cells were exposed to different amounts of the above-mentioned particles. Although most particle types are shown to be internalised (except Ni-particles), only Co-particles possessed cytotoxic effects. Furthermore, an impairment of the proliferative activity and a pro-inflammatory stimulation of endothelial cells were induced by exposure to Co- and, to a lesser extent, by SiO2-particles. If a pro-inflammatory stimulation of endothelial cells occurs in vivo, a chronic inflammation could be a possible consequence. 相似文献
212.
Maria Antonietta Aiello Francesco Micelli Luca Valente 《Canadian Metallurgical Quarterly》2007,11(6):650-658
Emerging techniques that use fiber-reinforced polymer (FRP) composites for strengthening and conservation of historic masonry are becoming increasingly accepted. In the last decades steel plates or wood frames were used for external confinement in containing the lateral dilation of masonry columns subjected to axial loads. In the last years FRP epoxy bonded strips or jackets were also employed to increase strength and ductility with encouraging results in terms of mechanical behavior and cost effectiveness. The behavior of masonry columns confined with FRP and subjected to axial compression is studied in this paper. An extended experimental investigation is presented in order to show the mechanical behavior of circular masonry columns built with calcareous blocks that may be commonly found in Italy and all over Europe in historical buildings. Different stacking schemes were used to build the columns, aiming to simulate the most common situations in existing masonry structures. Carbon FRP sheets were applied as external reinforcement; different amounts and different schemes of confining reinforcement were studied. The experiments include a new reinforcement technique made by using injected FRP bars through the columns cross section. Such a solution can be considered in place of a more traditional confinement, when external reinforcement must be avoided, or in addition to external reinforcement when an improved confinement effect is required. The structural behavior of masonry columns damaged under different levels of load and strengthened by using FRP reinforcements, was also investigated. Experimental results revealed the effectiveness of the FRP confinement for masonry columns, also for columns that were strongly predamaged before strengthening. A computation of the ultimate load was conducted using the Italian National Research Council recommendations to show an application of the design approach recently proposed in Italy. An existing analytical model, previously developed by the writers, was applied for computation of expected experimental values. 相似文献
213.
Cozzoli PD Snoeck E Garcia MA Giannini C Guagliardi A Cervellino A Gozzo F Hernando A Achterhold K Ciobanu N Parak FG Cingolani R Manna L 《Nano letters》2006,6(9):1966-1972
Tetrapod-shaped maghemite nanocrystals are synthesized by manipulating the decomposition of iron pentacarbonyl in a ternary surfactant mixture under mild thermal conditions. Adjustment of the reaction parameters allows for the systematic tuning of both the width and the length of the tetrapod arms, which grow preferentially along the 111 easy axis direction. Such degree of control leads to modulation of the magnetic behavior of the nanocrystals, which evolves systematically as their surface magnetization phase and shape anisotropy are progressively increased. 相似文献
214.
Newborn neurons in the adult hippocampus are regulated by many intrinsic and extrinsic cues. It is well accepted that elevated glucocorticoid levels lead to downregulation of adult neurogenesis, which this review discusses as one reason why psychiatric diseases, such as major depression, develop after long-term stress exposure. In reverse, adult neurogenesis has been suggested to protect against stress-induced major depression, and hence, could serve as a resilience mechanism. In this review, we will summarize current knowledge about the functional relation of adult neurogenesis and stress in health and disease. A special focus will lie on the mechanisms underlying the cascades of events from prolonged high glucocorticoid concentrations to reduced numbers of newborn neurons. In addition to neurotransmitter and neurotrophic factor dysregulation, these mechanisms include immunomodulatory pathways, as well as microbiota changes influencing the gut-brain axis. Finally, we discuss recent findings delineating the role of adult neurogenesis in stress resilience. 相似文献
215.
Impagliazzo A Krippahl L Ubbink M 《Chembiochem : a European journal of chemical biology》2005,6(9):1648-1653
The nitrite reductase-binding site on pseudoazurin has been determined by using NMR chemical-shift perturbations. It comprises residues in the hydrophobic patch surrounding the exposed copper ligand His81 as well as several positively charged residues. The binding site is similar for both redox states of pseudoazurin, despite differences in the binding mode. The results suggest that pseudoazurin binds in a well-defined orientation. Docking simulations provide a putative structure of the complex with a binding site on nitrite reductase that has several hydrophobic and polar residues as well as a ridge of negatively charged side chains and a copper-to-copper distance of 14 A. 相似文献
216.
217.
Fabiola Liscio Silvia Milita Cristiano Albonetti Pasquale D'Angelo Antonietta Guagliardi Norberto Masciocchi Raffaele Guido Della Valle Elisabetta Venuti Aldo Brillante Fabio Biscarini 《Advanced functional materials》2012,22(5):943-953
A multiscale investigation of N,N′‐bis(n‐octyl)‐x:y, dicyanoperylene‐3,4:9,10‐bis(dicarboximide), PDI8‐CN2, shows the same molecular arrangement in the bulk and in thin films sublimated on SiO2/Si wafers. Non‐conventional powder diffraction methods and theoretical calculations concur to provide a coherent picture of the crystalline structure. X‐ray diffraction (XRD) and atomic force microscopy (AFM) analyses of films of different thickness deposited at different substrate temperatures indicate the existence of two temperature‐dependent deposition regimes: a low‐temperature (room temperature) regime and a high‐temperature (80–120 °C) one, each characterized by different growth mechanisms. These mechanisms eventually result in different morphological and structural features of the films, which appear to be highly correlated with the trend of the electrical parameters that are measured in PDI8‐CN2‐based field‐effect transistors. 相似文献
218.
Shuyan Shao Wytse Talsma Matteo Pitaro Jingjin Dong Simon Kahmann Alexander Joseph Rommens Giuseppe Portale Maria Antonietta Loi 《Advanced functional materials》2021,31(11):2008478
To date, there are no reports of 3D tin perovskite being used as a semiconducting channel in field-effect transistors (FETs). This is probably due to the large amount of trap states and high p-doping typical of this material. Here, the first top-gate bottom-contact FET using formamidinium tin triiodide perovskite films is reported as a semiconducting channel. These FET devices show a hole mobility of up to 0.21 cm2 V−1 s−1, an ION/OFF ratio of 104, and a relatively small threshold voltage (VTH) of 2.8 V. Besides the device geometry, the key factor explaining this performance is the reduced doping level of the active layer. In fact, by adding a small amount of the 2D material in the 3D tin perovskite, the crystallinity of FASnI3 is enhanced, and the trap density and hole carrier density are reduced by one order of magnitude. Importantly, these transistors show enhanced parameters after 20 months of storage in a N2 atmosphere. 相似文献
219.
Hybrid Perovskites: Photophysics of Organic–Inorganic Hybrid Lead Iodide Perovskite Single Crystals (Adv. Funct. Mater. 16/2015) 下载免费PDF全文
220.
Hong‐Hua Fang Jie Yang Sampson Adjokatse Eelco Tekelenburg Machteld E. Kamminga Herman Duim Jianting Ye Graeme R. Blake Jacky Even Maria Antonietta Loi 《Advanced functional materials》2020,30(6)
2D perovskite materials have recently reattracted intense research interest for applications in photovoltaics and optoelectronics. As a consequence of the dielectric and quantum confinement effect, they show strongly bound and stable excitons at room temperature. Here, the band‐edge exciton fine structure and in particular its exciton and biexciton dynamics in high quality crystals of (PEA)2PbI4 are investigated. A comparison of bulk and surface exciton lifetimes yields a room temperature surface recombination velocity of 2 × 103 cm s?1 and an intrinsic lifetime of 185 ns. Biexciton emission is evidenced at room temperature, with a binding energy of ≈45 meV and a lifetime of 80 ps. At low temperature, exciton state splitting is observed, which is caused by the electron–hole exchange interaction. Transient photoluminescence resolves the low‐lying dark exciton state, with a bright/dark splitting energy estimated to be 10 meV. This work contributes to the understanding of the complex scenario of the elementary photoexcitations in 2D perovskites. 相似文献