全文获取类型
收费全文 | 274篇 |
免费 | 12篇 |
国内免费 | 2篇 |
专业分类
化学 | 246篇 |
晶体学 | 1篇 |
数学 | 16篇 |
物理学 | 25篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 12篇 |
2012年 | 23篇 |
2011年 | 17篇 |
2010年 | 10篇 |
2009年 | 10篇 |
2008年 | 23篇 |
2007年 | 26篇 |
2006年 | 20篇 |
2005年 | 22篇 |
2004年 | 14篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1974年 | 3篇 |
排序方式: 共有288条查询结果,搜索用时 15 毫秒
231.
Irene Quinzeni Vittorio Berbenni Doretta Capsoni Marcella Bini 《Journal of Solid State Electrochemistry》2018,22(7):2013-2024
Spinel ferrites are an amazing class of materials that can find application in different fields, from sensors and lithium-ion batteries to the intriguing biomedical field. For the use as anode in lithium-ion batteries, ZnFe2O4 is rather competitive due to low price, abundance, environmental benignity, working voltage of ~1.5 V, and, most importantly, a high theoretical specific capacity (~1072 mA h g?1). For its practical application, however, some issues must be overcome, in particular its fast capacity fading and poor rate capability resulting from an inherent low electronic conductivity. Possible strategies are represented by ferrite carbon coating/embedding, peculiar synthesis routes, and doping. In this frame, we synthesized Ca- and Al-doped ZnFe2O4 nanoparticles by using microwave-assisted combustion synthesis, followed by a classical carbon coating (determined as about 5 wt% by thermogravimetry). A good solubility of Ca and Al up to 25 atom% on both Zn and Fe sites was obtained. Cyclic voltammetries evidenced redox reactions involving Zn and Fe ions, but also the Al intervention could be supposed. Galvanostatic charge–discharge cycles proved that particularly Al ions were useful to improve the anode structural stability at high C rate (up to 3C), thanks to the stronger Al–O bonds with respect to Fe–O ones. A further improvement of capacities comes from the use of sodium alginate as binder to substitute polyvinylidene fluoride in the anode preparation. 相似文献
232.
Photocatalytic Water Oxidation by a Mixed‐Valent MnIII3MnIVO3 Manganese Oxo Core that Mimics the Natural Oxygen‐Evolving Center 下载免费PDF全文
Dr. Rami Al‐Oweini Dr. Andrea Sartorel Dr. Bassem S. Bassil Dr. Mirco Natali Dr. Serena Berardi Prof. Franco Scandola Prof. Ulrich Kortz Prof. Marcella Bonchio 《Angewandte Chemie (International ed. in English)》2014,53(42):11182-11185
The functional core of oxygenic photosynthesis is in charge of catalytic water oxidation by a multi‐redox MnIII/MnIV manifold that evolves through five electronic states (Si , where i=0–4). The synthetic model system of this catalytic cycle and of its S0→S4 intermediates is the expected turning point for artificial photosynthesis. The tetramanganese‐substituted tungstosilicate [MnIII3MnIVO3(CH3COO)3(A‐α‐SiW9O34)]6? (Mn4POM) offers an unprecedented mimicry of the natural system in its reduced S0 state; it features a hybrid organic–inorganic coordination sphere and is anchored on a polyoxotungstate. Evidence for its photosynthetic properties when combined with [Ru(bpy)3]2+ and S2O82? is obtained by nanosecond laser flash photolysis; its S0→S1 transition within milliseconds and multiple‐hole‐accumulating properties were studied. Photocatalytic oxygen evolution is achieved in a buffered medium (pH 5) with a quantum efficiency of 1.7 %. 相似文献
233.
Room-temperature, continuous-wave operation of an external-cavity quantum cascade laser (EC-QCL) is reported. Single-mode tuning range of 120 cm(-1) was achieved, from 7.96 to 8.84 microm. The gain chips utilized are based on the bound to continuum design and were fabricated as buried heterostructure lasers. Gap-free tuning (mode hops only on the external-cavity modes) is demonstrated for an antireflection-coated laser, just by grating rotation. The EC-QCL was implemented in a Littrow setup and an average power of 1.5 mW was obtained at 20 degrees C, while a peak power of 20 mW was obtained for a modified Littrow setup with the back extraction of light. 相似文献
234.
235.
Marcella Belcastro Tiziana Marino Nino Russo Marirosa Toscano 《Theoretical chemistry accounts》2006,115(5):361-369
Density functional theory was employed to investigate the molecular properties of new systems that serve as antioxidants in the marine environment. The B3LYP/6-311++G** protocol was used for all computations. Investigation, performed in gas phase and in solvent, was devoted mainly to the determination of the O–H bond dissociation enthalpies and the ionization potentials of examined compounds, since these quantities represent the most important parameters on which the biological activity can be rationalized. The results, interpreted in terms of conjugation and delocalization effects acting on molecules and all their possible radicals, showed that between the studied systems the hydroquinone derivatives have the greatest potentiality as antioxidants.Electronic Supplementary Material Supplementary material is available in the online version of this article at 相似文献
236.
Kabirov Dzhovidon Silvestri Teresa Niccoli Marcella Usacheva Tatiana Mayol Laura Biondi Marco Giancola Concetta 《Journal of Thermal Analysis and Calorimetry》2022,147(1):347-353
Journal of Thermal Analysis and Calorimetry - Curcumin (CURC) is endowed with many pharmacological properties, among these anti-inflammatory, antioxidant, antimicrobial, and anticancer activity.... 相似文献
237.
In this review, we summarize the recent development in modeling nuclear quantum effects at aqueous metal interfaces. First, we review the nuclear quantum effects on the water-metal interface at ultrahigh vacuum. Then, we illustrate the nuclear quantum effects at the potential of zero charge conditions. At last, we give some outlook for the perspective work in modeling the nuclear quantum effects at electrochemical interfaces and some practical simulation strategies. 相似文献
238.
Dr. Shakeel A. Shahid Dr. Madhu Nagaraj Nandini Chauhan Dr. Trent W. Franks Dr. Benjamin Bardiaux Dr. Michael Habeck Dr. Marcella Orwick‐Rydmark Prof. Dirk Linke Dr. Barth‐J. van Rossum 《Angewandte Chemie (International ed. in English)》2015,54(43):12602-12606
MAS‐NMR was used to study the structure and dynamics at ambient temperatures of the membrane‐anchor domain of YadA (YadA‐M) in a pellet of the outer membrane of E. coli in which it was expressed. YadA is an adhesin from the pathogen Yersinia enterocolitica that is involved in interactions with the host cell, and it is a model protein for studying the autotransport process. Existing assignments were sucessfully transferred to a large part of the YadA‐M protein in the E. coli lipid environment by using 13C‐13C DARR and PDSD spectra at different mixing times. The chemical shifts in most regions of YadA‐M are unchanged relative to those in microcrystalline YadA‐M preparations from which a structure has previously been solved, including the ASSA region that is proposed to be involved in transition‐state hairpin formation for transport of the soluble domain. Comparisons of the dynamics between the microcrystalline and membrane‐embedded samples indicate greater flexibility of the ASSA region in the outer‐membrane preparation at physiological temperatures. This study will pave the way towards MAS‐NMR structure determination of membrane proteins, and a better understanding of functionally important dynamic residues in native membrane environments. 相似文献
239.
240.
Marcella Pasqualetti Susanna Gorrasi Valeria Giovannini Martina Braconcini Massimiliano Fenice 《Molecules (Basel, Switzerland)》2022,27(3)
The investigation for novel unique extremozymes is a valuable business for which the marine environment has been overlooked. The marine fungus Clonostachys rosea IG119 was tested for growth and chitinolytic enzyme production at different combinations of salinity and pH using response surface methodology. RSM modelling predicted best growth in-between pH 3.0 and 9.0 and at salinity of 0–40‰, and maximum enzyme activity (411.137 IU/L) at pH 6.4 and salinity 0‰; however, quite high production (>390 IU/L) was still predicted at pH 4.5–8.5. The highest growth and activity were obtained, respectively, at pH 4.0 and 8.0, in absence of salt. The crude enzyme was tested at different salinities (0–120‰) and pHs (2.0–13.0). The best activity was achieved at pH 4.0, but it was still high (in-between 3.0 and 12.0) at pH 2.0 and 13.0. Salinity did not affect the activity in all tested conditions. Overall, C. rosea IG119 was able to grow and produce chitinolytic enzymes under polyextremophilic conditions, and its crude enzyme solution showed more evident polyextremophilic features. The promising chitinolytic activity of IG119 and the peculiar characteristics of its chitinolytic enzymes could be suitable for several biotechnological applications (i.e., degradation of salty chitin-rich materials and biocontrol of spoiling organisms, possibly solving some relevant environmental issues). 相似文献