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991.
Zahraa S. Al-Taie Barbara Bartholomew Christopher Cartmell Richard T. Froom Russell G. Kerr Rolf Kraehenbuehl Patrick J. Murphy Robert J. Nash Yana B. Penkova Alexander van Teijlingen 《Molecules (Basel, Switzerland)》2022,27(4)
The absolute stereochemistry of the marine alkaloid (+)-(R)-tiruchanduramine was established via a convergent total synthesis in six steps and 15.5% overall yield from Fmoc-D-Dab(Boc)-OH. 相似文献
992.
993.
Highly Efficient Triplet Photosensitizers: A Systematic Approach to the Application of IrIII Complexes containing Extended Phenanthrolines
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Yue Lu Dr. Niamh McGoldrick Dr. Frances Murphy Dr. Brendan Twamley Xiaoneng Cui Dr. Colm Delaney Dr. Gearóid M. Ó Máille Junsi Wang Prof. Dr. Jianzhang Zhao Prof. Dr. Sylvia M. Draper 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(32):11349-11356
A series of IrIII complexes, based on 1,10‐phenanthroline featuring aryl acetylene chromophores, were prepared and investigated as triplet photosensitizers. The complexes were synthesized by Sonogashira cross‐coupling reactions using a “chemistry‐on‐the‐complex” method. The absorption properties and luminescence lifetimes were successfully tuned by controlling the number and type of light‐harvesting group. Intense UV/Vis absorption was observed for the IrIII complexes with two light‐harvesting groups at the 3‐ and 8‐positions of the phenanthroline. The asymmetric IrIII complex (with a triphenylamine (TPA) and a pyrene moiety attached) exhibited the longest lifetime. Red emission was observed for all the complexes in deaerated solutions at room temperature. Their emission at low temperature (77 K) and nanosecond time‐resolved transient difference absorption spectra revealed the origin of their triplet excited states. The singlet‐oxygen (1O2) sensitization and triplet‐triplet annihilation (TTA)‐based upconversion were explored. Highly efficient TTA upconversion (ΦUC=28.1 %) and 1O2 sensitization (ΦΔ=97.0 %) were achieved for the asymmetric IrIII complex, which showed intense absorption in the visible region (λabs=482 nm, ?=50900 m ?1 cm?1) and had a long‐lived triplet excited state (53.3 μs at RT). 相似文献
994.
Cappozzo Andrea Greselin Francesca Murphy Thomas Brendan 《Advances in Data Analysis and Classification》2020,14(2):327-354
Advances in Data Analysis and Classification - In a standard classification framework a set of trustworthy learning data are employed to build a decision rule, with the final aim of classifying... 相似文献
995.
Advances in Data Analysis and Classification - We consider model-based clustering methods for continuous, correlated data that account for external information available in the presence of... 相似文献
996.
ABSTRACTWe compare recently proposed methods to compute the electronic state energies of the water molecule on a quantum computer. The methods include the phase estimation algorithm based on Trotter decomposition, the phase estimation algorithm based on the direct implementation of the Hamiltonian, direct measurement based on the implementation of the Hamiltonian and a specific variational quantum eigensolver, Pairwise VQE. After deriving the Hamiltonian using STO-3G basis, we first explain how each method works and then compare the simulation results in terms of gate complexity and the number of measurements for the ground state of the water molecule with different O–H bond lengths. Moreover, we present the analytical analyses of the error and the gate-complexity for each method. While the required number of qubits for each method is almost the same, the number of gates and the error vary a lot. In conclusion, among methods based on the phase estimation algorithm, the second-order direct method provides the most efficient circuit implementations in terms of the gate complexity. Moreover, Pairwise VQE serves the most practical method for near-term applications on the current available quantum computers. Finally the possibility of extending the calculation to excited states and resonances is discussed. 相似文献
997.
Oliver J. Turner Dr. David J. Hirst Prof. Dr. John A. Murphy 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(14):3026-3029
A radical domino cyclisation reaction of N-cyanamide alkenes, mediated by hydrogen atom transfer (HAT) has been developed. This method, using PhSiH3 and catalytic Fe(acac)3, allows for the synthesis of challenging (spiro)quinazolinone scaffolds from simple, tractable (hetero)aryl carboxylic acid and cyanamide building blocks. 相似文献
998.
W. L. McLaughlin J. M. Puhl A. Kovcs M. Baranyai I. Slezsk M. C. Saylor S. A. Saylor S. D. Miller M. Murphy 《Radiation Physics and Chemistry》1999,55(5-6):767-771
A new radiation dosimeter, consisting of an optically-stimulated polymer film containing a photofluorescent sensor, can serve as a routine dosimeter and radiographic imaging medium for high-dose applications in the absorbed dose range 0.1–100 kGy. The flexible, colorless, opalescent film having a uniform thickness of 0.240 (±0.005) mm or certain other films in the thickness range 0.08–0.60 mm, are available in large batches. They can be read rapidly with a simple table-top spectrofluorimeter, excitation wavelength (λ=450 nm) and emission wavelength (λ=670 nm), giving a type A uncertainty of dose evaluation of <±5% at 95% confidence level. It supplies either single integrated dose readings or two-dimensional radiographic images with relatively high spatial resolution. The present work focuses on the following gamma-ray response characteristics of the system: inter- and intra-batch reproducibility, pre- and post-irradiation stability, and dependence of dose interpretations on absorbed dose rate and irradiation temperature. 相似文献
999.
Luka
orevi Cataldo Valentini Nicola Demitri Ccile Mzire Magali Allain Marc Sall Andrea Folli Damien Murphy Samuel Maas‐Valero Eugenio Coronado Davide Bonifazi 《Angewandte Chemie (International ed. in English)》2020,59(10):4106-4114
Herein we report an efficient synthesis to prepare O‐doped nanographenes derived from the π‐extension of pyrene. The derivatives are highly fluorescent and feature low oxidation potentials. Using electrooxidation, crystals of cationic mixed‐valence (MV) complexes were grown in which the organic salts organize into face‐to‐face π‐stacks, a favorable solid‐state arrangement for organic electronics. Variable‐temperature electron paramagnetic resonance (EPR) measurements and relaxation studies suggest a strong electron delocalization along the longitudinal axis of the columnar π‐stacking architectures. Electric measurements of single crystals of the MV salts show a semiconducting behavior with a remarkably high conductivity at room temperature. These findings support the notion that π‐extension of heteroatom‐doped polycyclic aromatic hydrocarbons is an attractive approach to fabricate nanographenes with a broad spectrum of semiconducting properties and high charge mobilities. 相似文献
1000.
Matthew S. Klee Matthew D. Williams Imogene Chang Joseph Murphy 《Journal of separation science》1999,22(1):24-28
A new ECD, the HP 6890 Series Micro-ECD, was designed to address inherent deficiencies in classical electron capture detectors (ECD), especially with respect to sensitivity, linearity, dynamic range, and ruggedness. Several novel technologies were incorporated in the totally new design and were refined through practical testing and user feedback. Validation of the micro-ECD performance was accomplished through side-by-side testing of the Micro-ECD with previous ECDs following US EPA Contract Laboratory Program methods for pesticides and PCBs. In addition, extensive interviews were conducted with early users of the Micro-ECD who also had experience with other designs running a variety of ECD methods. The design and resulting performance improvements are described. 相似文献