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71.
Elemental mapping and quantitative analysis of Cu, Zn, and Fe in rat brain sections by laser ablation ICP-MS 总被引:1,自引:0,他引:1
This report details the application of laser ablation quadrupole ICP-MS for the (multi)elemental mapping of 100-μm-thick sections
of rat brain. The laser spot size used was 60 μm, and the laser scan speed was 120 μm s−1. The analysis was relatively rapid, allowing mapping of a whole brain thin section (≈1 cm2) in about 2 h. Furthermore, the method was amenable to multi-element data collection including the physiologically important
elements P and S and afforded sub μg g−1 detection limits for the important trace elements Cu and Zn. Calibrations were performed with pressed pellets of biological
certified reference materials, and the elemental distributions and concentrations of Cu, Zn, and Fe were determined in whole
rat brain sections. The distributions and concentration ranges for these elements were consistent with previous studies and
demonstrate the utility of this technique for rapid mapping of brain thin sections. 相似文献
72.
It is well observed that individual behaviour can have an effect on the efficiency of queueing systems. The impact of this behaviour on the economic efficiency of public services is considered in this paper where we present results concerning the congestion related implications of decisions made by individuals when choosing between facilities. The work presented has important managerial implications at a public policy level when considering the effect of allowing individuals to choose between providers. We show that in general the introduction of choice in an already inefficient system will not have a negative effect. Introducing choice in a system that copes with demand will have a negative effect. 相似文献
73.
Aharmim B Ahmed SN Amsbaugh JF Anthony AE Banar J Barros N Beier EW Bellerive A Beltran B Bergevin M Biller SD Boudjemline K Boulay MG Bowles TJ Browne MC Bullard TV Burritt TH Cai B Chan YD Chauhan D Chen M Cleveland BT Cox-Mobrand GA Currat CA Dai X Deng H Detwiler J DiMarco M Doe PJ Doucas G Drouin PL Duba CA Duncan FA Dunford M Earle ED Elliott SR Evans HC Ewan GT Farine J Fergani H Fleurot F Ford RJ Formaggio JA Fowler MM Gagnon N Germani JV Goldschmidt A Goon JT Graham K Guillian E 《Physical review letters》2008,101(11):111301
The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (nu_x) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54_-0.31;+0.33(stat)-0.34+0.36(syst)x10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Deltam2=7.59_-0.21;+0.19x10(-5) eV2 and theta=34.4_-1.2;+1.3 degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results. 相似文献
74.
Highly Efficient Dehydrogenative Coupling of Hydrosilanes with Amines or Amides Using Supported Gold Nanoparticles
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Dr. Takato Mitsudome Teppei Urayama Dr. Zen Maeno Dr. Tomoo Mizugaki Prof. Dr. Koichiro Jitsukawa Prof. Dr. Kiyotomi Kaneda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3202-3205
Hydroxyapatite‐supported gold nanoparticles (Au/HAP) can act as a highly active and reusable catalyst for the coupling of hydrosilanes with amines under mild conditions. Various silylamines can be selectively obtained from diverse combinations of equimolar amounts of hydrosilanes with amines including less reactive bulky hydrosilanes. This study also highlights the applicability of Au/HAP to the selective synthesis of silylamides through the coupling of hydrosilanes with amides, demonstrating the first example of an efficient heterogeneous catalyst. Moreover, Au/HAP shows high reusability and applicability for gram‐scale synthesis. 相似文献
75.
Headspace quantification of pure and aqueous solutions of binary mixtures of key volatile organic compounds in Swiss cheeses using selected ion flow tube mass spectrometry
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76.
Ruthenium‐Containing Linear Helicates and Mesocates with Tuneable p53‐Selective Cytotoxicity in Colorectal Cancer Cells
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Dr. Simon J. Allison Dr. David Cooke Francesca S. Davidson Prof. Paul I. P. Elliott Dr. Robert A. Faulkner Hollie B. S. Griffiths Owen J. Harper Omar Hussain Prof. P. Jane Owen‐Lynch Prof. Roger M. Phillips Prof. Craig R. Rice Samantha L. Shepherd Dr. Richard T. Wheelhouse 《Angewandte Chemie (International ed. in English)》2018,57(31):9799-9804
The ligands L1 and L2 both form separable dinuclear double‐stranded helicate and mesocate complexes with RuII. In contrast to clinically approved platinates, the helicate isomer of [Ru2( L1 )2]4+ was preferentially cytotoxic to isogenic cells (HCT116 p53?/?), which lack the critical tumour suppressor gene. The mesocate isomer shows the reverse selectivity, with the achiral isomer being preferentially cytotoxic towards HCT116 p53+/+. Other structurally similar RuII‐containing dinuclear complexes showed very little cytotoxic activity. This study demonstrates that alterations in ligand or isomer can have profound effects on cytotoxicity towards cancer cells of different p53 status and suggests that selectivity can be “tuned” to either genotype. In the search for compounds that can target difficult‐to‐treat tumours that lack the p53 tumour suppressor gene, [Ru2( L1 )2]4+ is a promising compound for further development. 相似文献
77.
Chih‐Hung Chou Jyh‐Cheng Chen Chia‐Cheng Tai I‐Wen Sun Jyh‐Myng Zen 《Electroanalysis》2008,20(7):771-775
We report here a nonenzymatic sensor by using a nanoporous platinum electrode to detect glucose directly. The electrode was fabricated by electrochemical deposition and dissolution of PtZn alloy in zinc chloride‐1‐ethyl‐3‐methylimidazolium chloride (ZnCl2‐EMIC) ionic liquid. Both SEM and electrochemical studies showed the evidences for the nanoporous characteristics of the as‐prepared Pt electrodes. Amperometric measurements allow observation of the electrochemical oxidation of glucose at 0.4 V (vs. Ag/AgCl) in pH 7.4 phosphate buffer solution. The sensor also demonstrates significant reproducibility in glucose detection; the higher the roughness factor of the Pt electrode, the lower the detection limit of glucose. The interfering species such as ascorbic acid and p‐acetamidophenol can be avoided by using a Pt electrode with a high roughness factor of 151. Overall, the nanoporous Pt electrode is promising for enzymeless detection of glucose at physiological condition. 相似文献
78.
79.
Ma Z Halling MD Solum MS Harper JK Orendt AM Facelli JC Pugmire RJ Grant DM Amick AW Scott LT 《The journal of physical chemistry. A》2007,111(10):2020-2027
13C chemical shift tensor data from 2D FIREMAT spectra are reported for 4,7-di-t-butylacenaphthene and 4,7-di-t-butylacenaphthylene. In addition, calculations of the chemical shielding tensors were completed at the B3LYP/6-311G** level of theory. While the experimental tensor data on 4,7-di-t-butylacenaphthylene are in agreement with theory and with previous data on polycyclic aromatic hydrocarbons, the experimental and theoretical data on 4,7-di-t-butylacenaphthene lack agreement. Instead, larger than usual differences are observed between the experimental chemical shift components and the chemical shielding tensor components calculated on a single molecule of 4,7-di-t-butylacenaphthene, with a root mean square (rms) error of +/-7.0 ppm. The greatest deviation is concentrated in the component perpendicular to the aromatic plane, with the largest value being a 23 ppm difference between experiment and theory for the 13CH2 carbon delta11 component. These differences are attributed to an intermolecular chemical shift that arises from the graphitelike, stacked arrangement of molecules found in the crystal structure of 4,7-di-t-butylacenaphthene. This conclusion is supported by a calculation on a trimer of molecules, which improves the agreement between experiment and theory for this component by 14 ppm and reduces the overall rms error between experiment and theory to 4.0 ppm. This intermolecular effect may be modeled with the use of nuclei independent chemical shieldings (NICS) calculations and is also observed in the isotropic 1H chemical shift of the CH2 protons as a 4.2 ppm difference between the solution value and the solid-state chemical shift measured via a 13C-1H heteronuclear correlation experiment. 相似文献
80.
Vibrational sum frequency generation spectroscopy is used to study the interactions of the charged soluble organic surfactant sodium dodecyl sulfate (SDS) with an insoluble 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayer at the air-aqueous interface. Results indicate that the surfactant species compete for surface sites in the mixed system, with a lower monolayer number density of DPPC molecules being observed in the presence of dodecyl sulfate anions at the interface. Spectroscopic results also indicate that fewer dodecyl sulfate chains reside at the interface when the insoluble DPPC film is present. Increased conformational ordering of the acyl chains of both the DPPC molecules and the interfacial dodecyl sulfate anions is observed in the mixed system. Additionally, charged surfactant SDS promotes the alignment of the interfacial water molecules even in the presence of a DPPC monolayer. 相似文献