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111.
We prove that every Kirchberg algebra in the UCT class has nuclear dimension 1. We first show that Kirchberg 2-graph algebras with trivial K0 and finite K1 have nuclear dimension 1 by adapting a technique developed by Winter and Zacharias for Cuntz algebras. We then prove that every Kirchberg algebra in the UCT class is a direct limit of 2-graph algebras to obtain our main theorem. 相似文献
112.
We present here a fine singularity analysis of solutions to the Laplace equation in special polygonal domains in the plane. We assume piecewise constant Neumann data on one component of the boundary. Our motivation is to study the so‐called Berg effect, which is explained in the introduction. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
113.
114.
Belén Abarca Rafael Ballesteros Rosa Adam Rafael Ballesteros-Garrido Frédéric R. Leroux Françoise Colobert Ibon Alkorta José Elguero 《Tetrahedron》2014
A dynamic 1H NMR study, together with DFT calculations, of bis-([1,2,3]triazolo)[1,5-a:5′,1′-k][1,10]phenanthroline 2 has allowed to identify the ring and open forms of a new example of ring/chain tautomerism, as well as their interconversion barriers (ring/ring and ring/open). The barrier of the exchange process between the chain forms and the ring form was found higher than the ‘racemization’ process in the closed form, so the ring opening does not contribute to the ‘racemization’. The di-1,10-methyl and di-1,10-iodo derivatives have been prepared and their properties calculated. 相似文献
115.
Daniele Giallombardo Adam C. Nevin William Lewis Christopher C. Nawrat Russell R.A. Kitson Christopher J. Moody 《Tetrahedron》2014
A synthesis of the naturally occurring xanthone toxyloxanthone B is described, in which the key step is the regioselective addition of a methyl salicylate to a substituted benzyne, followed by cyclization of the intermediate aryl anion to form the xanthone, the regiochemistry of the aryne addition being confirmed by X-ray crystallography. Subsequent introduction of the pyran ring by [3,3]-rearrangement and deprotection completed the synthesis. 相似文献
116.
Joanna Augustynowicz Olga G. Długosz-Grochowska Anna M. Kostecka-Gugała Maria Leja Michał K. Kruczek Adam Świderski 《Central European Journal of Chemistry》2014,12(4):519-527
This study was focused on the analysis of the contents (by HPLC-DAD) and antioxidant activity of phenolic compounds of aquatic higher plant Callitriche cophocarpa. The novelty of the work was: 1) the study of the species which is almost unknown in the context of investigations of bio-active compounds and, 2) the application of a unique L-band electron resonance spectroscopy (L-band EPR) to measure antioxidant activity of samples. The results were compared with those obtained for microalgae Chlorella and Spirulina which are widely distributed as the diet supplements. The obtained results are very promising with respect to the freeze-dried material of Callitriche, which revealed both high level of phenolic compounds (33 mg g?1 dry weight) and antioxidant activity (0.14 g of reduced DPPH· g?1 dry weight). An isoform of sinapic acid appeared to be the main fraction in this sample. The average content of the total phenolic compounds in Callitriche freeze-dried samples was ca. 43 or 25 times higher than in the case of the Chlorella or Spirulina samples, respectively. These samples showed also 16 times lower scavenging activity in relation to freeze-dried Callitriche material. 相似文献
117.
Clayton A. Whitmore Mariam I. Boules William J. Behof Justin R. Haynes Dmitry Koktysh Adam J. Rosenberg Mohammed N. Tantawy Wellington Pham 《Molecules (Basel, Switzerland)》2021,26(8)
Promethazine, an antihistamine drug used in the clinical treatment of nausea, has been demonstrated the ability to bind Abeta in a transgenic mouse model of Alzheimer’s disease. However, so far, all of the studies were performed in vitro using extracted tissues. In this work, we report the design and synthesis of a novel [11C]promethazine PET radioligand for future in vivo studies. The [11C]promethazine was isolated by RP-HPLC with radiochemical purity >95% and molar activity of 48 TBq/mmol. The specificity of the probe was demonstrated using human hippocampal tissues via autoradiography. 相似文献
118.
Carrier transport in gated 2D graphene monolayers is considered in the presence of scattering by random charged impurity centers with density n(i). Excellent quantitative agreement is obtained (for carrier density n>10(12) cm(-2)) with existing experimental data. The conductivity scales linearly with n/n(i) in the theory. We explain the experimentally observed asymmetry between electron and hole conductivities, and the high-density saturation of conductivity for the highest mobility samples. We argue that the experimentally observed saturation of conductivity at low density arises from the charged impurity induced inhomogeneity in the graphene carrier density which becomes severe for n less, similarn(i) approximately 10(12) cm(-2). 相似文献
119.
Pharmacological MRI (phMRI) experiments utilise fMRI time series methods to map the central effect of pharmaceutical compounds. The typical univariate maps may, however, integrate the effects of several different neurotransmitter systems or underlying mechanisms. The results may thus be spatially and/or mechanistically nonspecific. Intersubject correlation analysis based on the phMRI response amplitude can more directly identify patterns of functional connectivity underlying the central effects of an acutely administered compound. In this article, we extend this approach to experiments where the effects of one compound in modulating the response to another are of interest. Specifically, we show a modulation of the correlation structure of a probe compound (d-amphetamine) by pretreatment with the selective dopamine D3 receptor antagonist SB277011A in the rat. The strongest modifications in the correlation patterns occurred in connection with the ventral tegmental area, the source of mesolimbic dopamine projections and a key substrate in the reward system. 相似文献
120.
Marina Huber-Gedert Dr. Michał Nowakowski Dr. Ahmet Kertmen Dr. Lukas Burkhardt Dr. Natalia Lindner Dr. Roland Schoch Dr. Regine Herbst-Irmer Dr. Adam Neuba Lennart Schmitz Tae-Kyu Choi Dr. Jacek Kubicki Prof. Dr. Wojciech Gawelda Prof. Dr. Matthias Bauer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(38):9905-9918
A new base metal iron-cobalt dyad has been obtained by connection between a heteroleptic tetra-NHC iron(II) photosensitizer combining a 2,6-bis[3-(2,6-diisopropylphenyl)imidazol-2-ylidene]pyridine with 2,6-bis(3-methyl-imidazol-2-ylidene)-4,4′-bipyridine ligand, and a cobaloxime catalyst. This novel iron(II)-cobalt(III) assembly has been extensively characterized by ground- and excited-state methods like X-ray crystallography, X-ray absorption spectroscopy, (spectro-)electrochemistry, and steady-state and time-resolved optical absorption spectroscopy, with a particular focus on the stability of the molecular assembly in solution and determination of the excited-state landscape. NMR and UV/Vis spectroscopy reveal dissociation of the dyad in acetonitrile at concentrations below 1 mM and high photostability. Transient absorption spectroscopy after excitation into the metal-to-ligand charge transfer absorption band suggests a relaxation cascade originating from hot singlet and triplet MLCT states, leading to the population of the 3MLCT state that exhibits the longest lifetime. Finally, decay into the ground state involves a 3MC state. Attachment of cobaloxime to the iron photosensitizer increases the 3MLCT lifetime at the iron centre. Together with the directing effect of the linker, this potentially makes the dyad more active in photocatalytic proton reduction experiments than the analogous two-component system, consisting of the iron photosensitizer and Co(dmgH)2(py)Cl. This work thus sheds new light on the functionality of base metal dyads, which are important for more efficient and sustainable future proton reduction systems. 相似文献