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51.
Schneider G 《Journal of computer-aided molecular design》2012,26(1):115-120
Approximately 25 years ago the first computer applications were conceived for the purpose of automated ‘de novo’ drug design,
prominent pioneering tools being ALADDIN, CAVEAT, GENOA, and DYLOMMS. Many of these early concepts were enabled by innovative
techniques for ligand-receptor interaction modeling like GRID, MCSS, DOCK, and CoMFA, which still provide the theoretical
framework for several more recently developed molecular design algorithms. After a first wave of software tools and groundbreaking
applications in the 1990s—expressly GROW, GrowMol, LEGEND, and LUDI representing some of the key players—we are currently
witnessing a renewed strong interest in this field. Innovative ideas for both receptor and ligand-based drug design have recently
been published. We here provide a personal perspective on the evolution of de novo design, highlighting some of the historic
achievements as well as possible future developments of this exciting field of research, which combines multiple scientific
disciplines and is, like few other areas in chemistry, subject to continuous enthusiastic discussion and compassionate dispute. 相似文献
52.
New perthiophosphonic acid anhydrides (R-PS2)n with R = 2,4,6-tri-iso-propylphenyl and 2,4-di-tert-butyl-6-methylphenyl have been prepared. For the latter case, the isolation of the monomer (n = 1), the 2,4-di-tertbutyl-6-methylphenyl-dithioxophosphorane, and both dimers (n = 2), cis- and trans-2,4-bis(2,4-di-tertbutyl-6-methylphenyl)-2, 4-dithioxo-1, 3, 2, 4-dithiadiphosphetane, has been determined. The new cis and trans dithiadiphosphetanes and dithioxophosphoranes as well as the known compounds (2,4,6-trimethylphenyl-PS2)2 and 2,4,6-tri-tert-butylphenyl-PS2 are characterized by solution and high resolution solid-state 31P and 13C NMR spectroscopy. The existence of a dimer-monomer equilibrium is directly proved by 2D exchange 31P NMR spectroscopy. It is shown that the reaction of the monomer with methanol is faster than the reaction of the dimer with methanol. 相似文献
53.
54.
H.-J. Clar M. Reich R. Schieder G. Winnewisser Koichi M.T. Yamada 《Journal of Molecular Spectroscopy》1985,112(2):447-458
The ΔK = Δl = +1 transitions of the ν6 band of the CH3I molecule were measured by a tunable diode laser spectrometer. A newly designed Fabry-Perot étalon with a free spectral range of 0.00945 cm?1 was used to calibrate the line position very precisely. The present data were analyzed together with the previously reported transition wavenumbers, and precise molecular constants have been obtained. 相似文献
55.
Given a system of linear equations and inequalities inn variables, a famous result due to A. J. Hoffman (1952) says that the distance of any point in
n
to the solution set of this system is bounded above by the product of a positive constant and the absolute residual. We shall discuss explicit representations of this constant in dependence upon the pair of norms used for the estimation. A method for computing a special form of Hoffman constants is proposed. Finally, we use these results in the analysis of Lipschitz continuity for solutions of parametric quadratic programs. 相似文献
56.
Seifallah Abid Yohan Gisbert Mitsuru Kojima Nathalie Saffon-Merceron Jrme Cuny Claire Kammerer Gwnaël Rapenne 《Chemical science》2021,12(13):4709
Mastering intermolecular gearing is crucial for the emergence of complex functional nanoscale machineries. However, achieving correlated motion within trains of molecular gears remains highly challenging, due to the multiple degrees of freedom of each cogwheel. In this context, we designed and synthesised a series of star-shaped organometallic molecular gears incorporating a hydrotris(indazolyl)borate anchor to prevent diffusion on the surface, a central ruthenium atom as a fixed rotation axis, and an azimuthal pentaporphyrinic cyclopentadienyl cogwheel specifically labelled to monitor its motion by non-time-resolved Scanning Tunneling Microscopy (STM). Desymmetrisation of the cogwheels was first achieved sterically, i.e. by introducing one tooth longer than the other four. For optimal mechanical interactions, chemical labelling was also investigated as a preferential way to induce local contrast in STM images, and the electronic properties of one single paddle were modulated by varying the porphyrinic scaffold or the nature of the central metal. To reach such a structural diversity, our modular synthetic approach relied on sequential cross-coupling reactions on a penta(p-halogenophenyl)cyclopentadienyl ruthenium(ii) key building block, bearing a single pre-activated p-iodophenyl group. Chemoselective Sonogashira or more challenging Suzuki–Miyaura reactions allowed the controlled introduction of the tagged porphyrinic tooth, and the subsequent four-fold cross-couplings yielded the prototypes of pentaporphyrinic molecular gears for on-surface studies, incorporating desymmetrised cogwheels over 5 nm in diameter.Star-shaped cogwheel prototypes incorporating one sterically- or chemically-labelled porphyrinic paddle were designed and synthesised with the aim of achieving intermolecular gearing on surfaces. 相似文献
57.
The pure rotational spectra of H212C17O and H213C17O have been investigated in the frequency region between 8 and 360 GHz in the ground vibrational state. For both isotopic species the 17O nuclear quadrupole coupling constants and spin-rotation constants have been obtained. From both Q- and R-branch transitions a set of rotational constants and several distortion constants could be derived employing Watson's formalism in A reduction. The obtained rotational constants are in Megahertz:
H212C17O | H213C17O | |
281 965.0 (30) | 281 987.3 (19) | |
37 812.287(45) | 36 776.790(25) | |
33 214.523(31) | 32 412.920(19) |