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881.
[Structure: see text] The isokibdelones are an unprecedented family of polyketides produced by an Australian isolate of a rare actinomycete, Kibdelosporangium sp. The structures of the isokibdelones were assigned by spectroscopic analysis and chemical interconversion. A proposed biosynthesis requires a novel molecular twist that generates an unprecedented heterocyclic system and differentiates the isokibdelones from their kibdelone co-metabolites. SAR analysis on the isokibdelones further defines the anticancer pharmacophore of these novel polyketides. 相似文献
882.
Integrability of derivatives of inverses of maps of exponentially integrable distortion in the plane
James T. Gill 《Journal of Mathematical Analysis and Applications》2009,352(2):762-766
The K-quasiconformal maps form a category which is invariant under inversion, i.e. f and f−1 are simultaneously K-quasiconformal. Maps of exponentially integrable distortion are a useful class for extending the Beltrami equation to a degenerate setting. This class is not invariant under inversion. In this note we show that the inverses of homeomorphisms of exponentially p-integrable distortion have β-integrable distortion for all β<p, but not necessarily for β=p. 相似文献
883.
Pyrochlore-structured materials are very important materials due to their structural and conducting properties. These properties
can be further modified by changing processing conditions. In the present study, pyrochlore (Y2Ti2O7) is synthesized using high-energy ball milling. During various stages of ball milling, the ball-milled powder is taken for
investigating the structural and thermal properties. The replacement of Ti2O3 by TiO2 in nominal composition leads to lower ball milling duration to form Y2Ti2O7. Differential thermal analysis showed the single exothermic peak below 800 °C, which indicates formation of disordered pyrochlore
phase. The as prepared powders (40-h ball milled) were compacted and heat treated at 1,450 °C for 12 h. The conductivity of
sintered sample is found to be one order higher than earlier reported pure Y2Ti2O7 pyrochlore. 相似文献
884.
C. Amole M. D. Ashkezari G. B. Andresen M. Baquero-Ruiz W. Bertsche P. D. Bowe E. Butler C. L. Cesar S. Chapman M. Charlton A. Deller S. Eriksson J. Fajans T. Friesen M. C. Fujiwara D. R. Gill A. Gutierrez J. S. Hangst W. N. Hardy R. S. Hayano M. E. Hayden A. J. Humphries R. Hydomako S. Jonsell L. Kurchaninov N. Madsen S. Menary P. Nolan K. Olchanski A. Olin A. Povilus P. Pusa F. Robicheaux E. Sarid D. M. Silveira C. So J. W. Storey R. I. Thompson D. P. van der Werf J. S. Wurtele Y. Yamazaki 《Hyperfine Interactions》2012,212(1-3):101-107
The ALPHA experiment, located at CERN, aims to compare the properties of antihydrogen atoms with those of hydrogen atoms. The neutral antihydrogen atoms are trapped using an octupole magnetic trap. The trap region is surrounded by a three layered silicon detector used to reconstruct the antiproton annihilation vertices. This paper describes a method we have devised that can be used for reconstructing annihilation vertices with a good resolution and is more efficient than the standard method currently used for the same purpose. 相似文献
885.
William Alan Bertsche G. B. Andresen M. D. Ashkezari M. Baquero-Ruiz P. D. Bowe P. T. Carpenter E. Butler C. L. Cesar S. F. Chapman M. Charlton S. Eriksson J. Fajans T. Friesen M. C. Fujiwara D. R. Gill A. Gutierrez J. S. Hangst W. N. Hardy R. S. Hayano M. E. Hayden A. J. Humphries J. L. Hurt R. Hydomako S. Jonsell L. Kurchaninov N. Madsen S. Menary P. Nolan K. Olchanski A. Olin A. Povilus P. Pusa F. Robicheaux E. Sarid D. M. Silveira C. So J. W. Storey R. I. Thompson D. P. van der Werf J. S. Wurtele Y. Yamazaki 《Hyperfine Interactions》2012,212(1-3):61-67
In efforts to trap antihydrogen, a key problem is the vast disparity between the neutral trap energy scale ( $\sim\!50\,\upmu\mathrm{eV}$ ), and the energy scales associated with plasma confinement and space charge (~1 eV). In order to merge charged particle species for direct recombination, the larger energy scale must be overcome in a manner that minimizes the initial antihydrogen kinetic energy. This issue motivated the development of a novel injection technique utilizing the inherent nonlinear nature of particle oscillations in our traps. We demonstrated controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm or tenuous plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination. The nature of this injection overcomes some of the difficulties associated with matching the energies of the charged species used to produce antihydrogen. 相似文献
886.
An FP Bai JZ Balantekin AB Band HR Beavis D Beriguete W Bishai M Blyth S Boddy K Brown RL Cai B Cao GF Cao J Carr R Chan WT Chang JF Chang Y Chasman C Chen HS Chen HY Chen SJ Chen SM Chen XC Chen XH Chen XS Chen Y Chen YX Cherwinka JJ Chu MC Cummings JP Deng ZY Ding YY Diwan MV Dong L Draeger E Du XF Dwyer DA Edwards WR Ely SR Fang SD Fu JY Fu ZW Ge LQ Ghazikhanian V Gill RL Goett J Gonchar M Gong GH Gong H Gornushkin YA Greenler LS Gu WQ Guan MY Guo XH Hackenburg RW Hahn RL Hans S He M He Q 《Physical review letters》2012,108(17):171803
The Daya Bay Reactor Neutrino Experiment has measured a nonzero value for the neutrino mixing angle θ(13) with a significance of 5.2 standard deviations. Antineutrinos from six 2.9 GWth reactors were detected in six antineutrino detectors deployed in two near (flux-weighted baseline 470 m and 576 m) and one far (1648 m) underground experimental halls. With a 43,000 ton-GWth-day live-time exposure in 55 days, 10,416 (80,376) electron-antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to expected number of antineutrinos at the far hall is R=0.940±0.011(stat.)±0.004(syst.). A rate-only analysis finds sin(2)2θ(13)=0.092±0.016(stat.)±0.005(syst.) in a three-neutrino framework. 相似文献
887.
D He HC Nguyen BR Hayes-Gill Y Zhu JA Crowe GF Clough CA Gill SP Morgan 《Optics letters》2012,37(15):3060-3062
What is believed to be the first fully integrated two-dimensional complementary metal oxide semiconductor (CMOS) imaging array for laser Doppler blood flow imaging is demonstrated. The sensor has 64×64 pixels and includes both analog and digital on-chip processing electronics. This offers several potential advantages over commercial sensors as the processing is tailored to the signals of interest and the data bottleneck that exists between the sensor and processing electronics is overcome. To obtain a space efficient design over 64×64 pixels means that standard processing electronics used off-chip cannot be implemented. Images of both simulated blood flow responses and a blood flow occlusion test demonstrate the capability. 相似文献
888.
In Tae Kim Sang Woo Lee Tae Hyoung Kwak Jung Youl Lee Hyang Suk Park So Young Kim Chang Min Lee Hoi Eun Jung Jun‐Gill Kang Tack‐Jin Kim Hee‐Jung Kang ChangMoon Park Ronald L. Elsenbaumer 《Macromolecular rapid communications》2002,23(9):551-554
Oxidative coupling reaction of 1‐hexyl–3,4‐dimethylpyrrole affords a conjugated conducting poly(1‐hexyl‐3,4‐dimethyl‐2,5‐pyrrolylene) (PHDP), which is completely soluble in common organic solvents. The luminescence of PHDP is comparable to that of poly(N‐vinylcarbazole) (PVK), which has been widely used in electroluminescence devices. The quantum efficiency of PHDP is 2.5 times higher than that of PVK. A rationalization is presented relating the conductivity of PHDP to its polymer structure. 相似文献
889.