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991.
Jenkins MH Phillips BS Zhao Y Holmes MR Schmidt H Hawkins AR 《Optics Communications》2011,284(16-17):3980-3982
The use of scattered light images is shown to be an attractive method for the characterization of optofluidic waveguides. The method is shown to be capable of measuring waveguide propagation losses and transmissions between solid and liquid-core structures. Measurement uncertainties are considered and characterized and were typically less than 15%. 相似文献
992.
Androić D Armstrong DS Arvieux J Bailey SL Beck DH Beise EJ Benesch J Benmokhtar F Bimbot L Birchall J Bosted P Breuer H Capuano CL Chao YC Coppens A Davis CA Ellis C Flores G Franklin G Furget C Gaskell D Gericke MT Grames J Guillard G Hansknecht J Horn T Jones MK King PM Korsch W Kox S Lee L Liu J Lung A Mammei J Martin JW McKeown RD Micherdzinska A Mihovilovic M Mkrtchyan H Muether M Page SA Papavassiliou V Pate SF Phillips SK Pillot P Pitt ML Poelker M Quinn B Ramsay WD Real JS Roche J 《Physical review letters》2011,107(2):022501
We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasielastic scattering on the deuteron, at backward angles (lab scattering angle of 108°) for Q2 = 0.22 GeV2/c2 and 0.63 GeV2/c2 at beam energies of 362 and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single-photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (πN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasistatic deuterium approximation, and is also in agreement with theory. 相似文献
993.
It is shown that random duty-cycle errors in quasi-phase-matching (QPM) nonlinear optical devices enhance the efficiency of processes far from the QPM peak. An analytical theory is shown to agree well with numerical solutions of second-harmonic generation (SHG) in disordered QPM gratings. The measured efficiency of 1550?nm band SHG in a periodically poled lithium niobate (PPLN) waveguide away from the QPM peak agrees with observations of domain disorder in a PPLN wafer by Zygo interferometry. If suppression of parasitic nonlinear interactions is important in a specific application of QPM devices, control of random duty-cycle errors is critical. 相似文献
994.
G. Savard R. C. Pardo S. Baker C. N. Davids A. Levand D. Peterson D. G. Phillips T. Sun R. Vondrasek B. J. Zabransky G. P. Zinkann 《Hyperfine Interactions》2011,199(1-3):301-309
The Californium Rare Ion Breeder Upgrade (CARIBU) to the ATLAS superconducting linac facility is currently being commissioned. It provides low-energy and re-accelerated beams of neutron-rich isotopes obtained from 252Cf fission. The fission products from a 252Cf source are stopped in a large high-intensity gas catcher, thermalized and extracted through an RFQ cooler, accelerated to 50 kV and mass separated in a high-resolution separator before being sent to either an ECR charge breeder for post-acceleration through the ATLAS linac or to a low-energy experimental area. This approach gives access to beams of very neutron-rich isotopes, many of which have not been available at low or Coulomb barrier energies previously. These beams provide unique opportunities for measurements along the r-process path. To take advantage of these unique possibility, the reaccelerated beams from CARIBU will be made available at the experimental stations of ATLAS to serve equipment such as Gammasphere, HELIOS and the reaction spectrometers. In addition, the Canadian Penning Trap (CPT) mass spectrometer has been moved to the CARIBU low-energy experimental area and a new injection line has been built. The new injection line consists of a RFQ buncher sitting on a 50 kV high-voltage platform that will accumulate the mass separated 50 kV radioactive beams, cool and extract them as a pulsed beam of 3 keV. This beam can be sent either to a tape station for diagnostics and tuning, or a cryogenic linear trap for preparation before transfer to the high-precision Penning trap where the mass measurements will take place. Initial CARIBU commissioning is proceeding with a 2 mCi source that will be replaced by a 100 mCi source as the commissioning proceeds. Final operation will use a 1 Ci source and attain yield in excess of 107 ions/sec for the most intense beams at low energy, an order of magnitude less for reaccelerated beams. 相似文献
995.
Bhinde T Phillips TK Clarke SM Arnold T Parker JE 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):15-18
In this letter, the phase behavior of a saturated alkylamide, heptanamide (C(7)), adsorbed on the surface of graphite using synchrotron X-ray diffraction is presented. The diffraction patterns indicate that heptanamide undergoes a solid-solid phase transition in the monolayer at 330 K from pgg symmetry at lower temperatures to p2 symmetry at high temperatures. Other alkylamides with similar carbon chain lengths do not show this phase change, making the C(7) homologue unusual. 相似文献
996.
Stewart KW Phillips AR Whiting L Jüllig M Middleditch MJ Cooper GJ 《Rapid communications in mass spectrometry : RCM》2011,25(22):3387-3395
We describe a new, simple, robust and efficient method based on direct‐tissue matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF) mass spectrometry that enables consistent semi‐quantitation of peptide hormones in isolated pancreatic islets from normal and diabetic rodents. Prominent signals were measured that corresponded to all the main peptide hormones present in islet‐endocrine cells: (α‐cells) glucagon, glicentin‐related polypeptide/GRPP; (β‐cells) insulin I, insulin II, C‐peptide I, C‐peptide II, amylin; (δ‐cells) somatostatin‐14; and (PP‐cells), and pancreatic polypeptide. The signal ratios coincided with known relative hormone abundances. The method demonstrated that severe insulin deficiency is accompanied by elevated levels of all non‐β‐cell‐hormones in diabetic rat islets, consistent with alleviation of paracrine suppression of hormone production by non‐β‐cells. It was also effective in characterizing hormonal phenotype in hemizygous human‐amylin transgenic mice that express human and mouse amylin in approx. equimolar quantities. Finally, the method demonstrated utility in basic peptide‐hormone discovery by identifying a prominent new Gcg‐gene‐derived peptide (theoretical monoisotopic molecular weight 3263.5 Da), closely related to but distinct from GRPP, in diabetic islets. This peptide, whose sequence is HAPQDTEENARSFPASQTEPLEDPNQINE in Rattus norvegicus, could be a peptide hormone whose roles in physiology and metabolic disease warrant further investigation. This method provides a powerful new approach that could provide important new insights into the physiology and regulation of peptide hormones in islets and other endocrine tissues. It has potentially wide‐ranging applications that encompass endocrinology, pharmacology, phenotypic analysis in genetic models of metabolic disease, and hormone discovery, and could also effectively limit the numbers of animals required for such studies. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
997.
In diffraction from some icosahedral quasicrystals, diffuse scattering is concentrated on arcs in TEM diffraction patterns. The new Ti-Mn icosahedral phase produces much more intense arcs than previously observed in quasicrystals, allowing a significantly deeper study of them. 相似文献
998.
We use an effective field theory for short-range forces (SREFT) to analyze systems of three identical bosons interacting via a two-body potential that generates a scattering length, a, which is large compared to the range of the interaction, ?. The amplitude for the scattering of one boson off a bound state of the other two is computed to next-to-next-to-leading order (N2LO) in the ?/a expansion. At this order, two pieces of three-body data are required as input in order to renormalize the amplitude (for fixed a). We apply our results to a model system of three Helium-4 atoms, which are assumed to interact via the TTY potential. We generate N2LO predictions for atom-dimer scattering below the dimer breakup threshold using the bound-state energy of the shallow Helium-4 trimer and the atom-dimer scattering length as our two pieces of three-body input. Based on the convergence pattern of the SREFT expansion, as well as differences in the predictions of two renormalization schemes, we conclude that our N2LO phase- shift predictions will receive higher-order corrections of < 0.2 %. In contrast, the prediction of SREFT for the binding energy of the “deep” trimer of Helium-4 atoms displays poor convergence. 相似文献
999.
Ayodele Oladeji Lukasz Sojka Zhuoqi Tang David Furniss Andrew Phillips Angela Seddon Trevor Benson Slawomir Sujecki 《Optical and Quantum Electronics》2014,46(4):593-602
The experimentally obtained luminescence characteristics of a praseodymium (Pr $^{3+})$ doped chalcogenide glass fiber are studied numerically using a rate equation approach. The numerical model includes both the radiative and non-radiative transition paths whilst it neglects the up-conversion processes. Photoluminescence spectra at mid-infrared wavelengths ranging from 3.5 to 6 ${\upmu }$ m were obtained by using two pump wavelengths: 1.55 and 1.94 ${\upmu }$ m. A good agreement between the experiment and theory is obtained for the photoluminescence decay profiles. 相似文献
1000.
Katherine A. Koenig Ken E. Sakaie Mark J. Lowe Jian Lin Lael Stone Robert A. Bermel Erik B. Beall Stephen M. Rao Bruce D. Trapp Micheal D. Phillips 《Magnetic resonance imaging》2014