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331.
Dr. Bob C. Schroeder Dr. Zhe Li Michael A. Brady Dr. Gregório Couto Faria Dr. Raja Shahid Ashraf Dr. Christopher J. Takacs John S. Cowart Dr. Duc T. Duong Kar Ho Chiu Ching‐Hong Tan Dr. João T. Cabral Prof. Alberto Salleo Prof. Michael L. Chabinyc Prof. James R. Durrant Prof. Iain McCulloch 《Angewandte Chemie (International ed. in English)》2014,53(47):12870-12875
Cost‐effective, solution‐processable organic photovoltaics (OPV) present an interesting alternative to inorganic silicon‐based solar cells. However, one of the major remaining challenges of OPV devices is their lack of long‐term operational stability, especially at elevated temperatures. The synthesis of a fullerene dumbbell and its use as an additive in the active layer of a PCDTBT:PCBM‐based OPV device is reported. The addition of only 20 % of this novel fullerene not only leads to improved device efficiencies, but more importantly also to a dramatic increase in morphological stability under simulated operating conditions. Dynamic secondary ion mass spectrometry (DSIMS) and TEM are used, amongst other techniques, to elucidate the origins of the improved morphological stability. 相似文献
332.
Dr. Cameron E. Workman Dr. Pushan Bag Bridgie Cawthon Fidaa H. Ali Dr. Nathan G. Brady Prof. Barry D. Bruce Prof. Brian K. Long 《Angewandte Chemie (International ed. in English)》2023,62(43):e202306572
Styrene-maleic acid copolymers (SMAs), and related amphiphilic copolymers, are promising tools for isolating and studying integral membrane proteins in a native-like state. However, they do not exhibit this ability universally, as several reports have found that SMAs and related amphiphilic copolymers show little to no efficiency when extracting specific membrane proteins. Recently, it was discovered that esterified SMAs could enhance the selective extraction of trimeric Photosystem I from the thylakoid membranes of thermophilic cyanobacteria; however, these polymers are susceptible to saponification that can result from harsh preparation or storage conditions. To address this concern, we herein describe the development of α-olefin-maleic acid copolymers (αMAs) that can extract trimeric PSI from cyanobacterial membranes with the highest extraction efficiencies observed when using any amphiphilic copolymers, including diisobutylene-co-maleic acid (DIBMA) and functionalized SMA samples. Furthermore, we will show that αMAs facilitate the formation of photosystem I-containing nanodiscs that retain an annulus of native lipids and a native-like activity. We also highlight how αMAs provide an agile, tailorable synthetic platform that enables fine-tuning hydrophobicity, controllable molar mass, and consistent monomer incorporation while overcoming shortcomings of prior amphiphilic copolymers. 相似文献
333.
We construct a CAT(0) group containing a finitely presented subgroup with infinitely many conjugacy classes of finite-order
elements. Unlike previous examples (which were based on right-angled Artin groups) our ambient CAT(0) group does not contain
any rank 3 free abelian subgroups. We also construct examples of groups of type F
n
inside mapping class groups, Aut(), and Out() which have infinitely many conjugacy classes of finite-order elements.
相似文献
334.
We first point out that the subpixel response function is another kernel function in digital imaging. Then we show that the subpixel response function of CMOS imaging sensor pixels can be measured with an aperture array pixel mask in a single-shot image capture. Our technique permits high-resolution subpixel response function measurement of imaging pixels for superresolution imaging applications. 相似文献
335.
Mason PE Neilson GW Kline SR Dempsey CE Brady JW 《The journal of physical chemistry. B》2006,110(27):13477-13483
Neutron diffraction with isotopic substitution (NDIS) experiments and molecular dynamics (MD) simulations have been used to characterize the structure of aqueous guanidinium carbonate (Gdm2CO3) solutions. The MD simulations found very strong hetero-ion pairing in Gdm2CO3 solution and were used to determine the best structural experiment to demonstrate this ion pairing. The NDIS experiments confirm the most significant feature of the MD simulation, which is the existence of strong hetero-ion pairing between the Gdm+ and CO3(2-) ions. The neutron structural data also support the most interesting feature of the MD simulation, that the hetero-ion pairing is sufficiently strong as to lead to nanometer-scale aggregation of the ions. The presence of such clustering on the nanometer length scale was then confirmed using small-angle neutron scattering experiments. Taken together, the experiment and simulation suggest a molecular-level explanation for the contrasting denaturant properties of guanidinium salts in solution. 相似文献
336.
Guizzunti G Brady TP Malhotra V Theodorakis EA 《Journal of the American Chemical Society》2006,128(13):4190-4191
The chemical origin of the norrisolide-induced irreversible Golgi vesiculation was studied using a variety of norrisolide probes. This natural product was found to bind to a receptor on the Golgi membranes using the perhydroindane core fragment as the recognition element. The acetylated gamma-lactol-gamma-lactone side chain of norrisolide is essential for the irreversible Golgi vesiculation and can be replaced by other electrophilic motifs without loss of biological function. In particular, compound 10 reproduces the cellular phenotype of the natural product. 相似文献
337.
Mason PE Neilson GW Enderby JE Saboungi ML Cuello G Brady JW 《The Journal of chemical physics》2006,125(22):224505
The techniques of neutron diffraction with isotopic substitution (NDIS) and molecular dynamics (MD) simulations have been used to examine the rotational conformation of the exocyclic hydroxymethyl group of D-glucopyranose. First order H/D NDIS experiments were performed on the H6 position in 3m aqueous glucose solutions where the average coherent scattering length of the exchangeable hydrogen atoms was zero (i.e., all correlations between exchangeable hydrogen atoms and other atoms cancel and thus are not present in the scattering data). This H6 experimental result suggests that no single conformation for the C4-C5-C6-O6 dihedral reproduces the observed scattering data well, but that a mixture of the gg and gt conformations, which has been suggested by NMR experiments, gives a reasonable agreement between the MD and experimental data. 相似文献
338.
A combined experimental and trajectory study of vibrationally state-selected NO2+ collisions with Ne, Ar, Kr, and Xe is presented. Ne, Ar, and Kr are similar in that only dissociation to the excited singlet oxygen channel is observed; however, the appearance energies vary by approximately 4 eV between the three rare gases, and the variation is nonmonotonic in rare gas mass. Xe behaves quite differently, allowing efficient access to the ground triplet state dissociation channel. For all four rare gases there are strong effects of NO2+ vibrational excitation that extend over the entire collision energy range, implying that vibration influences the efficiency of collision to internal energy conversion. Bending excitation is more efficient than stretching; however, bending angular momentum partially counters the enhancement. Direct dynamics trajectories for NO2+ + Kr reproduce both the collision energy and vibrational state effects observed experimentally and reveal that intracomplex charge transfer is critical for the efficient energy transfer needed to drive dissociation. The strong vibrational effects can be rationalized in terms of bending, and to a lesser extent, stretching distortion enhancing transition to the Kr+ -NO2 charge state. 相似文献
339.
Code verification answers the question: “Is this code solving the equations correctly?” Validation answers the question: “Is this code solving the correct equations?” Code verification must be performed before attempting validation and is the focus of this paper. Here we present a novel method of applying the method of manufactured solutions (MMS) to finite volume multiphase codes. MMS is a procedure for generating analytic source terms and adding them to the governing equations such that the numerical solution converges to a previously determined analytic (manufactured) solution. This is a powerful method for generating exact benchmark solutions which can test the most general capabilities of a code. We present a series of manufactured solutions (MS) ranging from single-phase to multiphase flows to test all aspects of an example code. The chief obstacle to applying MMS to multiphase flow lies in the discontinuous nature of the material properties at the interface. An extension of the MMS procedure to multiphase flow is presented here using an adaptive marching tetrahedron style algorithm to compute the source terms near the interface. We also present guidelines for the use of the MMS to help locate coding mistakes (i.e. bugs). This is accomplished by the use of progressively simpler MS and material property variations. 相似文献
340.