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51.
O'Dea AR Curtis AF Green NJ Timmel CR Hore PJ 《The journal of physical chemistry. A》2005,109(5):869-873
Monte Carlo simulations of the effects of weak magnetic fields on the recombination of interacting radical pairs undergoing free diffusion in solution have been performed, with the aim of determining the influence on the low field effect of the magnetic dipolar coupling between the radicals. The suppression of singlet-triplet interconversion in the radical pair by the dipolar interaction is found to be pronounced at magnetic field strengths comparable to the hyperfine interactions in the radicals, to the extent that the low field effect is completely abolished. The averaging of the dipolar coupling by the translational diffusion of the radicals around one another is relatively efficient in the presence of strong magnetic fields but becomes ineffective in weak applied fields where the strength of the dipolar interaction is independent of the orientation of the inter-radical vector. Low field effects are only likely to be observed if the motion of the radical pair is restricted in some way so as to increase the likelihood that, having separated to the large distance required for the dipolar interaction to have a negligible effect, the radicals subsequently encounter and have the opportunity to recombine. 相似文献
52.
The problem of two‐dimensional tracer advection on the sphere is extremely important in modeling of geophysical fluids and has been tackled using a variety of approaches. A class of popular approaches for tracer advection include ‘incremental remap’ or cell‐integrated semi‐Lagrangian‐type schemes. These schemes achieve high‐order accuracy without the need for multistage integration in time, are capable of large time steps, and tend to be more efficient than other high‐order transport schemes when applied to a large number of tracers over a single velocity field. In this paper, the simplified flux‐form implementation of the Conservative Semi‐LAgrangian Multi‐tracer scheme (CSLAM) is reformulated using quadratic curves to approximate the upstream flux volumes and Gaussian quadrature for integrating the edge flux. The high‐order treatment of edge fluxes is motivated because of poor accuracy of the CSLAM scheme in the presence of strong nonlinear shear, such as one might observe in the midlatitudes near an atmospheric jet. Without the quadratic treatment of upstream edges, we observe at most second‐order accuracy under convergence of grid resolution, which is returned to third‐order accuracy under the improved treatment. A shallow‐water barotropic instability also reveals clear evidence of grid imprinting without the quadratic correction. Consequently, these tests reveal a problem that might arise in tracer transport near nonlinearly sheared regions of the real atmosphere, particularly near cubed‐sphere panel edges. Although CSLAM is used as the foundation for this analysis, the conclusions of this paper are applicable to the general class of incremental remap schemes. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
53.
Christiane Fernandes James L. Wardell Janet M. S. Skakle 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):o499-o502
The molecule of 2-(hydroxymethyl)-1,3-propanediol, C4H10O3, lies across a mirror plane in space group P21/m, with disorder of both terminal hydroxyl H atoms. The molecules are linked by three O—H⋯O hydrogen bonds which combine to form sheets; in each O—H⋯O bond, the H atom resonates between the two O atoms. In the crystal structure of N,N′-bis[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]malonamide, C11H22N2O8, the molecule lies about a twofold axis and has four strong hydrogen bonds which form a mixture of chains and dimers; these combine to give a three-dimensional supramolecular framework. 相似文献
54.
Dendritic Glycopolymer as Drug Delivery System for Proteasome Inhibitor Bortezomib in a Calcium Phosphate Bone Cement: First Steps Toward a Local Therapy of Osteolytic Bone Lesions 下载免费PDF全文
55.
Dr. Christiane Lang Sebastian Bestgen Dr. Alexander Welle Rouven Müller Prof. Peter W. Roesky Prof. Christopher Barner‐Kowollik 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(42):14728-14731
A platform technology for the creation of spatially resolved surfaces encoded with a monolayer consisting of different metal complexes was developed. The concept entails the light‐triggered activation of a self‐ assembled monolayer (SAM) of UV‐labile anchors, that is, phenacylsulfides, and the subsequent cycloaddition of selected diene‐functionalized metal complexes at defined areas on the surface. The synthesis and characterization of the metal complexes for the UV‐light assisted anchoring on the surface and a detailed study of a short‐chain oligomer model system in solution confirm the high efficiency of the photoreaction. The hybrid materials obtained by this concept can potentially be utilized for the design of highly valuable catalytic or (opto‐)electronic devices. 相似文献
56.
Marius Durea Radu Strugariu Christiane Tammer 《Journal of Optimization Theory and Applications》2017,175(3):738-763
The aim of this paper is to address new approaches, in separate ways, to necessary and, respectively, sufficient optimality conditions in constrained vector optimization. In this respect, for the necessary optimality conditions that we derive, we use a kind of vectorial penalization technique, while for the sufficient optimality conditions we make use of an appropriate scalarization method. In both cases, the approaches couple a basic technique (of penalization or scalarization, respectively) with several results in variational analysis and optimization obtained by the authors in the last years. These combinations allow us to arrive to optimality conditions which are, in terms of assumptions made, new. 相似文献
57.
58.
Ergot alkaloids are toxins and important pharmaceuticals which are produced biotechnologically on an industrial scale. They have been identi?ed in two orders of fungi and three families of higher plants. The most important producers are fungi of the genera Claviceps, Penicillium and Aspergillus (all belonging to the Ascomycota). Chemically, ergot alkaloids are characterised by the presence of a tetracyclic ergoline ring, and can be divided into three classes according to their structural features, i.e. amide- or peptide-like amide derivatives of D-lysergic acid and the clavine alkaloids. Signi?cant progress has been achieved on the molecular biological and biochemical investigations of ergot alkaloid biosynthesis in the last decade. By gene cloning and genome mining, gene clusters for ergot alkaloid biosynthesis have been identi?ed in at least 8 different ascomycete species. Functions of most structure genes have been assigned to reaction steps in the biosynthesis of ergot alkaloids by gene inactivation experiments or biochemical characterisation of the overproduced proteins. 相似文献
59.
The label-free time-resolved reflectometric interference spectroscopy has been used to study the interaction of the human
estrogen receptor alpha (ERa) and different types of ligands. Different possible sensor surface coatings including various
estrogen derivatives were evaluated for their suitability for detection of ERa. The determination of the kinetic and thermodynamic
constants was carried out for the interaction in the heterogeneous phase as well as for the interaction in homogeneous phase.
In addition, the affinity of 11 ligands ranging from natural hormones and pharmaceuticals to endocrine disrupting chemicals
(EDCs) has been determined with this label-free assay format. 相似文献
60.
Christiane Kraus 《Constructive Approximation》2011,33(2):191-217
The aim of this paper is to extend the classical maximal convergence theory of Bernstein and Walsh for holomorphic functions
in the complex plane to real analytic functions in ℝ
N
. In particular, we investigate the polynomial approximation behavior for functions F:L→ℂ, L={(Re z,Im z):z∈K}, of the structure F=g[`(h)]F=g\overline{h}, where g and h are holomorphic in a neighborhood of a compact set K⊂ℂ
N
. To this end the maximal convergence number ρ(S
c
,f) for continuous functions f defined on a compact set S
c
⊂ℂ
N
is connected to a maximal convergence number ρ(S
r
,F) for continuous functions F defined on a compact set S
r
⊂ℝ
N
. We prove that ρ(L,F)=min {ρ(K,h)),ρ(K,g)} for functions F=g[`(h)]F=g\overline{h} if K is either a closed Euclidean ball or a closed polydisc. Furthermore, we show that min {ρ(K,h)),ρ(K,g)}≤ρ(L,F) if K is regular in the sense of pluripotential theory and equality does not hold in general. Our results are based on the theory
of the pluricomplex Green’s function with pole at infinity and Lundin’s formula for Siciak’s extremal function Φ. A properly chosen transformation of Joukowski type plays an important role. 相似文献