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61.
We present valence-to-core X-ray emission spectroscopy of Ti, TiO, and TiO2 by means of a double crystal von Hamos spectrometer based on full-cylinder highly annealed pyrolytic graphite mosaic crystals. We demonstrate that, using a double crystal configuration, an energy resolution of E/ΔE ≈ 2,700 can be achieved in a compact setup using cylindrically curved optics with a radius of curvature of 50 mm. The stated energy resolution proved to be high enough to identify and determine chemical shifts of the Kβ2,5 and Kβ″ emission lines of both oxides. The experimental results are supported by calculations with the ab initio package OCEAN and compared with literature values. 相似文献
62.
Ina Schubert Christian Huck Philipp Krber Frank Neubrech Annemarie Pucci Maria Eugenia Toimil‐Molares Christina Trautmann Jochen Vogt 《Advanced Optical Materials》2016,4(11):1838-1845
Because of its extended surface area porous gold is of potential interest for surface‐enhanced spectroscopy methods. Optical properties of porous and smooth gold nanowires of similar diameter are analyzed with infrared spectroscopy and modeled with finite‐difference time‐domain simulations. By electrochemical deposition in ion‐track etched polymer smooth gold and gold–silver alloy nanowires are synthesized. Porous gold nanowires are subsequently obtained by dealloying. The porosity clearly affects important plasmonic characteristics, resulting in a strong redshift of the resonant wavelength, and significant line broadening, which can be convincingly explained by effective Drude parameters related to a lowered average electron density and a higher electron scattering in the porous gold, respectively. Finally, the sensing performance of porous wires is tested by surface‐enhanced infrared absorption. The measurements show a similar vibrational signal contrast for smooth and porous wires. This is explained by simulations which reveal that the nanowire near‐field modeled with bulk gold data is higher and thus accordingly the vibrational signal is enhanced compared to nanowires modeled with the effective Drude parameters of porous gold. This means that the advantages offered by the larger surface of porous wires are counterbalanced by lower near‐field strength. 相似文献
63.
Although key tumorigenic and tumor-suppressive factors have been unveiled over the last several decades, cancer remains the most life-threatening disease. Multiomic analyses of patient samples and an in-depth understanding of tumorigenic processes have rapidly revealed unexpected pathologic associations of new cellular factors previously overlooked in cancer biology. In this regard, the newly discovered activities of human aminoacyl-tRNA synthases (ARSs) deserve attention not only for their pathological significance in tumorigenesis but also regarding diagnostic and therapeutic implications. ARSs are not only essential enzymes covalently linking substrate amino acids to cognate tRNAs for protein synthesis but also function as regulators of cellular processes by sensing different cellular conditions. With their catalytic role in protein synthesis and their regulatory role in homeostasis, functional alterations or dysregulation of ARSs might be pathologically associated with tumorigenesis. This review focuses on the potential implications of ARS genes and proteins in different aspects of cancer based on various bioinformatic analyses and experimental data. We also review their diverse activities involving extracellular secretion, protein–protein interactions, and amino acid sensing, which are related to cancers. The newly discovered cancer-related activities of ARSs are expected to provide new opportunities for detecting, preventing and curing cancers.Subject terms: Mechanisms of disease, Nutrient signalling, Phosphorylation, Cancer metabolism, Cancer genomics 相似文献
64.
The great advantage of microreactors is associated with an extremely large surface-to-volume ratio. Hence, microreactors permit promising operating conditions, such as almost-perfect heat or mass transfer. This, of course, requires that the hydrodynamics is well understood. The hydrodynamics of a liquid/liquid slug flow in a micro-capillary is characterized by a complex vortex structure in both the disperse and the continuous phase. The disperse phase, in our investigations, is not wetting the walls and, thus, a thin film of the continuous phase persist between the disperse phase and the wall. Due to this phenomenon, a relative movement between disperse and continuous phase is possible and, indeed, observed. Understanding of these complex phenomena allows for a control of the hydrodynamics, and thus, to tailor the heat and mass transport in a desired manner. Apparently, several effects influence the hydrodynamics. The main dimensionless groups are a Reynolds number, a Capillary number, and the ratio of viscosities and densities of both phases. To study the physics of this complex two-liquid system, a modified level-set method in conjunction with an immersed-boundary formulation is engaged. Presently, the simulations are time-dependent and axially-symmetric in nature. The mesh resolution represents a challenge, as the spatial resolution has to resolve the thin film between the disperse phase and the wall adequately. All simulations are implemented within the software OpenFOAM. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
65.
Internal electrodes, adjacent to insulating walls at defined zeta potential, lead to a non-continuous potential distribution at the wall. Hence, simplified treatment appears problematic due to the singularity of the electrical field strength. To avoid this difficulty, we develop a hybrid model, which solves the electrical problem, including a resolution of the EDL, while the flow problem is solved in the fluid bulk only. We apply this hybrid model to investigate the position of internal electrodes with regard to their influence onto the flow field, driven by electroosmosis in a modular rectangular microchannel. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
66.
Martin Gerlach Lars Anklamm Alexander Antonov Inna Grigorieva Ina Holfelder Birgit Kanngießer Herbert Legall Wolfgang Malzer Christopher Schlesiger Burkhard Beckhoff 《Journal of Applied Crystallography》2015,48(5):1381-1390
Highly annealed pyrolytic graphite (HAPG) is an advanced type of pyrolytic graphite that, as a mosaic crystal, combines high integral reflectivity with a very low mosaicity of typically less than 0.1°. When used as dispersive X‐ray optics, a high resolving power has been observed, rendering HAPG very suitable for applications in high‐resolution X‐ray spectroscopy, which conventionally relies on ideal crystals. For the design and modelling of HAPG crystals in applications requiring high spectral resolution, the diffraction properties must be known very accurately. To close this gap, a comprehensive characterization of HAPG crystals was performed that allows for modelling of the diffraction properties in different diffraction orders over a broad spectral range. The crystal properties under investigation are the mosaic spread, the peak reflectivity and the intrinsic reflection width. The investigations were carried out for different thickness crystal films, which were mounted adhesively on a substrate. It is shown that the diffraction properties are strongly correlated to the grade of adhesion, which depends crucially on the substrate material and its surface properties. The investigations were performed using monochromated tunable synchrotron radiation of high spectral purity with a high‐precision experimental setup and calibrated detection devices at the electron storage ring BESSY II. 相似文献
67.
Summary: The barbituric acid moiety of the presented dyes shows multifunctional properties like acidochromism, solvatochromism, and adjustable hydrogen-bonding pattern for molecular recognition. Hydrogen-bonding ability, acidity and solvatochromic effects are studied for a series of N-alkyl substituted 5-(4-nitrophenyl)-barbiturates. Solvatochromism and metal ion complexation are also investigated using chromophoric thiobarbituric acid derivatives. 相似文献
68.
Ina Dix Christian Doll Henning Hopf Peter G. Jones 《European journal of organic chemistry》2002,2002(15):2547-2556
4-(2-Ethynylphenyl)pyridine ( 10 ), 3-(2-ethynylphenyl)pyridine ( 11 ), 2-(2-trimethylsilylethynylphenyl)pyridine ( 26 ), and 3-ethynyl-2-phenylpyridine ( 13 ) were prepared from readily available pyridine precursors by standard coupling reactions. Pyrolysis of 10 at 810 °C/0.5 Torr provided benzo[f]isoquinoline ( 45 ) and the benzopentalene dimer 47 . Pyrolysis of 11 (820 °C/0.5 Torr) afforded benzo[f]quinoline ( 50 ), benzo[h]isoquinoline ( 52 ), and a mixture of isomers of 47 . Pyrolysis of 13 (820 °C/0.3 Torr) provided benzo[h]quinoline ( 56 ) and the novel azulene derivative azuleno[1,2-b]pyridine ( 58 ). When 26 was desilylated by treatment with TBAF in THF/water, the unusual “dimerization” product 37 was produced; its structure was confirmed by X-ray structural analysis. The mechanisms of these transformations are discussed. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002) 相似文献
69.
Holger Zitt Ina Dix Henning Hopf Peter G. Jones 《European journal of organic chemistry》2002,2002(14):2298-2307
An efficient synthesis of [2.2]paracyclophane-4,15-dicarboxylic acid ( 11 ) from [2.2]paracyclophane ( 8 ) has been developed. The diacid was converted via the diazide 14 into the 4,15-diisocyanato[2.2]paracyclophane ( 15 ), a versatile intermediate that could be transformed into many new pseudo-geminally substituted derivatives of 8 . For example, treatment of 15 with alcohols provided the carbamates 16 and 17 . On treatment of 15 with diisopropylamine, the urea 18 was obtained, whereas reduction with lithium aluminium hydride afforded the cyclic urea 20 . Hydrolysis of 15 furnished the diamine 19 , which was used as a reusable spacer in a [2+2]photoaddition experiment. Thus, treatment of 19 with trans-cinnamoyl chloride ( 25 ) provided the bis(amide) 26 , which on irradiation in acetone ring-closed to give the cyclobutane 28 . Saponification of this yielded 3,4-diphenyl-1,2-cyclobutanedicarboxylic acid ( 27 , β-truxinic acid) and returned the spacer system 19 , both in quantitative yield. The X-ray structures of 15 and 20 are reported. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002) 相似文献
70.