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91.
P. Astier G. Bernardi G. Carugno J. Chauveau P. Chrysicopoulou J. Dumarchez M. Ferro-Luzzi F. Kovacs A. Letessier-Selvon J. -M. Levy M. J. Murtagh J. -M. Perreau Y. Pons J. L. Stone A. -M. Touchard F. Vannucci P. Wanderer D. H. White 《Physics letters. [Part B]》1989,220(4):646-652
A search for νμ→νe and
oscillations has been conducted with the AGS wide-band neutrino beam at the Brookhaven National Laboratory. We find more νe (
e) interactions than were expected on the basis of the number of incident νe (
e) calculated as part of the neutrino beam. The excess is about a factor two over the expectation, the statistical significance being about two and a half standard deviations for νe and weaker for
e. 相似文献
92.
D. H. Brick A. M. Shapiro M. Widgoff E. D. Alyea Jr. T. Fuess E. S. Hafen P. Haridas R. I. Hulsizer C. Milstene I. A. Pless R. K. Yamamoto F. Grard R. Dolfini S. Ratti R. Di Marco M. Kalelkar R. J. Plano P. E. Stamer S. Dado J. Goldberg R. Heifetz A. Levy W. M. Bugg T. Handler E. L. Hart Y. Eisenberg U. Karshon 《Zeitschrift fur Physik C Particles and Fields》1986,32(1):59-63
The total hadron multiplicity and the multiplicity in the three-jet events ine + e ?-annihilation are considered. The formula for the total multiplicity (with account for the heavy quark contribution) agrees well with experiment. The value of the multiplicity for three-jet events is predicted. 相似文献
93.
A high‐order element‐based Galerkin method is developed to solve the non‐divergent barotropic vorticity equation (BVE). The solution process involves solving a conservative transport equation for the vorticity fields and a Poisson equation for the stream function fields. The discontinuous Galerkin method is employed for solving the transport equation and a spectral element method (continuous Galerkin) is used for the Poisson equation. A third‐order strong stability preserving explicit Runge–Kutta scheme is used for time integration. A series of tests have been performed to validate the model, which include the evolution of an idealized tropical cyclone and interaction of dual vortices in close proximity. The numerical convergence study is performed by solving the BVE on the sphere where the analytic solution is known. The test results are consistent with physical observations, and the model exhibits exponential convergence. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
94.
Price JL Shental-Bechor D Dhar A Turner MJ Powers ET Gruebele M Levy Y Kelly JW 《Journal of the American Chemical Society》2010,132(43):15359-15367
Asparagine glycosylation is one of the most common and important post-translational modifications of proteins in eukaryotic cells. N-glycosylation occurs when a triantennary glycan precursor is transferred en bloc to a nascent polypeptide (harboring the N-X-T/S sequon) as the peptide is cotranslationally translocated into the endoplasmic reticulum (ER). In addition to facilitating binding interactions with components of the ER proteostasis network, N-glycans can also have intrinsic effects on protein folding by directly altering the folding energy landscape. Previous work from our laboratories (Hanson et al. Proc. Natl. Acad. Sci. U.S.A. 2009, 109, 3131-3136; Shental-Bechor, D.; Levy, Y. Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 8256-8261) suggested that the three sugar residues closest to the protein are sufficient for accelerating protein folding and stabilizing the resulting structure in vitro; even a monosaccharide can have a dramatic effect. The highly conserved nature of these three proximal sugars in N-glycans led us to speculate that introducing an N-glycosylation site into a protein that is not normally glycosylated would stabilize the protein and increase its folding rate in a manner that does not depend on the presence of specific stabilizing protein-saccharide interactions. Here, we test this hypothesis experimentally and computationally by incorporating an N-linked GlcNAc residue at various positions within the Pin WW domain, a small β-sheet-rich protein. The results show that an increased folding rate and enhanced thermodynamic stability are not general, context-independent consequences of N-glycosylation. Comparison between computational predictions and experimental observations suggests that generic glycan-based excluded volume effects are responsible for the destabilizing effect of glycosylation at highly structured positions. However, this reasoning does not adequately explain the observed destabilizing effect of glycosylation within flexible loops. Our data are consistent with the hypothesis that specific, evolved protein-glycan contacts must also play an important role in mediating the beneficial energetic effects on protein folding that glycosylation can confer. 相似文献
95.
Soriano Del Amo D Wang W Jiang H Besanceney C Yan AC Levy M Liu Y Marlow FL Wu P 《Journal of the American Chemical Society》2010,132(47):16893-16899
The Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is the standard method for bioorthogonal conjugation. However, current Cu(I) catalyst formulations are toxic, hindering their use in living systems. Here we report that BTTES, a tris(triazolylmethyl)amine-based ligand for Cu(I), promotes the cycloaddition reaction rapidly in living systems without apparent toxicity. This catalyst allows, for the first time, noninvasive imaging of fucosylated glycans during zebrafish early embryogenesis. We microinjected embryos with alkyne-bearing GDP-fucose at the one-cell stage and detected the metabolically incorporated unnatural sugars using the biocompatible click chemistry. Labeled glycans could be imaged in the enveloping layer of zebrafish embryos between blastula and early larval stages. This new method paves the way for rapid, noninvasive imaging of biomolecules in living organisms. 相似文献
96.
97.
Aprile E Arisaka K Arneodo F Askin A Baudis L Behrens A Bokeloh K Brown E Bruch T Bruno G Cardoso JM Chen WT Choi B Cline D Duchovni E Fattori S Ferella AD Gao F Giboni KL Gross E Kish A Lam CW Lamblin J Lang RF Levy C Lim KE Lin Q Lindemann S Lindner M Lopes JA Lung K Undagoitia TM Mei Y Fernandez AJ Ni K Oberlack U Orrigo SE Pantic E Persiani R Plante G Ribeiro AC Santorelli R dos Santos JM Sartorelli G Schumann M Selvi M Shagin P Simgen H Teymourian A Thers D Vitells O Wang H Weber M 《Physical review letters》2011,107(13):131302
We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time-projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows the selection of only the innermost 48 kg as the ultralow background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in the signal region with an expected background of (1.8 ± 0.6) events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic weakly interacting massive particle (WIMP) nucleon scattering cross sections above 7.0 × 10(-45) cm(2) for a WIMP mass of 50 GeV/c(2) at 90% confidence level. 相似文献
98.
E. Man�� J. A. Behr J. Billowes T. Brunner M. Brodeur F. Buchinger J. E. Crawford J. Dilling S. Ettenauer C. D. P. Levy A. Voss M. R. Pearson 《Hyperfine Interactions》2011,199(1-3):357-363
Collinear laser spectroscopy with reverse-extracted cooled bunched beams was performed at TRIUMF with radioactive ion beams. Surface-ionized 78,78mRb ions were injected into TITAN??s cooler-buncher, and reverse-extracted to the laser beam line. There they were neutralised and excited with a counter-propagating laser beam. The fluorescence signal from the D 2 line was recorded with a photomultiplier tube. The cooler provided typically 50 ion bunches per second, with each bunch containing approximately 105 ions, temporally distributed with a 1.6 ??s width. A hardware gate was set on the signal, suppressing the background by four orders of magnitude. 相似文献
99.
The lowest ionization potential and transition energies of methane are calculated by a second-order perturbation expansion, using a limited basis of gaussian-type orbitals. An attempt is made to rationalize the choice of basis atomic orbitals. This procedure yields 13·8 eV for the first ionization potential and 10·4 eV for the lowest allowed transition provided a diffuse molecular orbital is added to describe the excited state (the experimental values are 13·6 and 9·7 eV). These two values include contributions of -1·0 and -0·70 eV, respectively, from an approximate optimization of the basis atomic orbitals and of +0·50 and +0·25 eV from electron correlation. 相似文献
100.
Brick DH Widgoff M Beilliere P Lutz P Narjoux JL Gelfand N Alyea ED Bloomer M Bober J Busza W Cole B Frank TA Fuess TA Grodzins L Hafen ES Haridas P Huang D Huang HZ Hulsizer R Kistiakowsky V Ledoux RJ Milstene C Noguchi S Oh SH Pless IA Steadman S Stoughton TB Suchorebrow V Tether S Trepagnier PC Wadsworth BF Wu Y Yamamoto RK Cohn HO Calligarich E Castoldi C Dolfini R Introzzi G Ratti S Badiak M DiMarco R Jacques PF Kalelkar M Plano RJ Stamer PE Brucker EB Koller EL Alexander G Grunhaus J 《Physical review D: Particles and fields》1990,41(3):765-773