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961.
We compute the next-to-next-to-leading-order (NNLO) QCD corrections to the thrust distribution in electron-positron annihilation. The corrections turn out to be sizable, enhancing the previously known next-to-leading-order prediction by about 15%. Inclusion of the NNLO corrections significantly reduces the theoretical renormalization scale uncertainty on the prediction of the thrust distribution. 相似文献
962.
4,5‐Dihydro‐1,2,3‐oxadiazole: A Very Elusive Key Intermediate in Various Important Chemical Transformations 下载免费PDF全文
Prof. Dr. Klaus Banert Neeraj Singh Benjamin Fiedler Prof. Dr. Joachim Friedrich Marcus Korb Prof. Dr. Heinrich Lang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(43):15092-15099
4,5‐Dihydro‐1,2,3‐oxadiazoles are postulated to be key intermediates in the industrial synthesis of ketones from alkenes, in the alkylation of DNA in vivo, and in the decomposition of N‐nitrosoureas; they are also a subject of great interest for theoretical chemists. In the presented report, the formation of 4,5‐dihydro‐1,2,3‐oxadiazole and the subsequent decay into secondary products have been studied by NMR monitoring analysis. The elusive properties evading characterization have now been confirmed by 1H, 13C, and 15N NMR spectroscopy, and relevant 2D experiments at very low temperatures. Our experiments with suitably substituted N‐nitrosoureas using thallium(I) alkoxides as bases under apolar conditions answer important questions on the existence and the secondary products of 4,5‐dihydro‐1,2,3‐oxadiazole. 相似文献
963.
M.Sc. Amelie L. Bartuschat Karina Wicht Prof. Dr. Markus R. Heinrich 《Angewandte Chemie (International ed. in English)》2015,54(35):10294-10298
Tertiary amides, which usually occur as cis/trans mixtures, can be effectively shifted to the cis conformation by placing a positive charge in close proximity to the amide carbonyl. This effect was used to prepare cis‐configured prolyl amides and to facilitate a strongly rotamer‐dependent radical cyclization. 相似文献
964.
Ultrafast Charge‐Transfer Reactions of Indoline Dyes with Anchoring Alkyl Chains of Varying Length in Mesoporous ZnO Solar Cells 下载免费PDF全文
Dr. Egmont Rohwer Iulia Minda Gabriele Tauscher Christoph Richter Dr. Hidetoshi Miura Prof. Dr. Derck Schlettwein Prof. Dr. Heinrich Schwoerer 《Chemphyschem》2015,16(5):943-948
Dye‐sensitized solar cells based on a mesoporous ZnO substrate were sensitized with the indoline derivatives DN91, DN216 and DN285. The chromophore is the same for each of these dyes. They differ from each other in the length of an alkyl chain, which provides a second anchor to the ZnO surface and prolongs cell lifetime. Ultrafast transient absorption measurements reveal a correlation between the length of the alkyl chain and the fastest electron‐injection process. The depopulation of the excited state and the associated emergence of the oxidized molecules are dominant spectral features in the transient absorption of the dyes with shorter alkyl chains. A slower picosecond‐scale decay proceeds at constant rate for all three derivatives and is assigned to electron transfer into the trap states of ZnO. All assignments are in good agreement with a higher quantum efficiency of charge injection leading to higher short‐circuit currents Jsc for dyes with shorter alkyl chains. 相似文献
965.
David Amschl Jörg Neddens Daniel Havas Stefanie Flunkert Roland Rabl Heinrich Römer Edward Rockenstein Eliezer Masliah Manfred Windisch Birgit Hutter-Paier 《BMC neuroscience》2013,14(1):1-14
Background
Progressive accumulation of α-synuclein (α-Syn) protein in different brain regions is a hallmark of synucleinopathic diseases, such as Parkinson’s disease, dementia with Lewy bodies and multiple system atrophy. α-Syn transgenic mouse models have been developed to investigate the effects of α-Syn accumulation on behavioral deficits and neuropathology. However, the onset and progression of pathology in α-Syn transgenic mice have not been fully characterized. For this purpose we investigated the time course of behavioral deficits and neuropathology in PDGF-β human wild type α-Syn transgenic mice (D-Line) between 3 and 12 months of age.Results
These mice showed progressive impairment of motor coordination of the limbs that resulted in significant differences compared to non-transgenic littermates at 9 and 12 months of age. Biochemical and immunohistological analyses revealed constantly increasing levels of human α-Syn in different brain areas. Human α-Syn was expressed particularly in somata and neurites of a subset of neocortical and limbic system neurons. Most of these neurons showed immunoreactivity for phosphorylated human α-Syn confined to nuclei and perinuclear cytoplasm. Analyses of the phenotype of α-Syn expressing cells revealed strong expression in dopaminergic olfactory bulb neurons, subsets of GABAergic interneurons and glutamatergic principal cells throughout the telencephalon. We also found human α-Syn expression in immature neurons of both the ventricular zone and the rostral migratory stream, but not in the dentate gyrus.Conclusion
The present study demonstrates that the PDGF-β α-Syn transgenic mouse model presents with early and progressive accumulation of human α-Syn that is accompanied by motor deficits. This information is essential for the design of therapeutical studies of synucleinopathies. 相似文献966.
967.
Sandip Rooj Varun Thakur Uwe Gohs Udo Wagenknecht Anil K. Bhowmick Gert Heinrich 《先进技术聚合物》2011,22(12):2257-2263
Blends of polypropylene (PP) and epoxidized natural rubber (ENR) were prepared by an in‐line electron induced reactive processing technique. The mixing was done in a Brabender mixing chamber coupled with an electron accelerator. The effect of sequence of electron treatment on the compatibilization of non‐polar PP and polar ENR was investigated in the presence of triallyl cyanurate (TAC). Finally, the resulting blends were characterized by different techniques, namely, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), tensile tests, and rheological studies. Generation of phase coupling and chemical compatibilization were observed from FTIR analysis. DMA studies showed enhanced high‐temperature modulus (above the glass transition temperature of both components) followed up by lowering in the tan δ peak. Rheological studies showed increase in modulus at low frequencies. Electron treatment and incorporation of rubber phase into PP showed significant effect on the degree of crystallinity of the blends, which was characterized by DSC study. The results obtained from FTIR, DMA, SEM, rheological studies, and tensile tests strongly affirmed that electron induced reactive processing of PP in presence of TAC before adding of ENR performed the best amongst all samples modified with electrons investigated in this study. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
968.
V. Sember A. Mašláni P. Křenek M. Heinrich R. Nimmervoll H. Pauser M. Hrabovský 《Plasma Chemistry and Plasma Processing》2011,31(5):755-770
Optical emission spectroscopy has been used to investigate the characteristics of a plasma jet produced by a steam arc cutting
torch operated in air at atmospheric pressure. A procedure has been developed for simultaneous determination of temperature
and pressure in the plasma jet as well as an effective nonequilibrium factor. It is based on comparison of a few experimental
and simulated spectral quantities. The experimental data were obtained from the spectrum of Hβ and OII lines centred at 480 nm. The existence of the shock wave structure characteristic of an underexpanded jet can clearly
be deduced from the measured properties. In the first expansion region, the centreline pressure drops from about 1.4 atm at
the nozzle exit to about 0.7 atm a few tenths of millimeter downstream. On the contrary, the centreline temperature remains
almost unchanged within this region and reaches the value of about 23,000 K. 相似文献
969.
970.
Rausch MH Lehmann J Leipertz A Fröba AP 《Physical chemistry chemical physics : PCCP》2011,13(20):9525-9533
The present study shows that dynamic light scattering (DLS) is capable of measuring mutual diffusion coefficients for binary mixtures of ionic liquids (ILs) with different molecular liquids over the complete composition range. Evidence is given that the light scattering signals are related to true molecular binary diffusion. The method stands out due to its ability to work non-invasively in macroscopic thermodynamic equilibrium with reasonable accuracy and within convenient measurement periods. Compared with other techniques, mixtures with distinctly higher viscosities can be probed. For exemplary binary mixtures of 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO(4)]) with acetone, acetonitrile, dichloromethane, ethanol, or water as well as of 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MeSO(3)]) with acetone, water, or methanol, mutual diffusivity data were measured over a wide range of composition at a temperature of 293.15 K. In general, the mutual diffusivity increases with increasing mole fraction of the molecular liquid and similarities to aqueous solutions of classical inorganic salts can be found. The characteristic behavior of the mutual diffusion coefficients is influenced by the nature of the chosen molecular liquid. For IL water mixtures, low light scattering intensities were observed despite the large refractive index difference of the pure components. The reason for this behavior may be the existence of water clusters in the mixtures. Additional measurements for IL acetone mixtures at temperatures ranging from 278.15 K to 323.15 K showed that the temperature dependence of the mutual diffusivity can be represented by Arrhenius functions and is increasing for decreasing mole fractions of acetone. 相似文献