首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   138篇
  免费   1篇
化学   87篇
晶体学   2篇
数学   10篇
物理学   40篇
  2021年   3篇
  2020年   2篇
  2015年   2篇
  2014年   3篇
  2013年   7篇
  2012年   2篇
  2011年   8篇
  2010年   7篇
  2009年   3篇
  2007年   5篇
  2006年   4篇
  2005年   2篇
  2002年   4篇
  2001年   3篇
  2000年   3篇
  1999年   2篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   3篇
  1989年   1篇
  1988年   1篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1982年   1篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   4篇
  1974年   3篇
  1973年   3篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   3篇
  1966年   4篇
  1965年   10篇
  1964年   3篇
  1963年   4篇
  1962年   3篇
  1961年   2篇
  1960年   2篇
  1959年   2篇
  1958年   1篇
  1957年   3篇
  1956年   1篇
  1955年   1篇
  1953年   1篇
排序方式: 共有139条查询结果,搜索用时 15 毫秒
81.
82.
The quadrupole moments of the 3/2 and 5/2 states in103Rh have been determined by measuring the precession of the gamma-ray angular distribution following Coulomb excitation;16O and32S beams have been used. The structure of the negative-parity states in103Rh is found to be in agreement with the model of Arima and Iachello.  相似文献   
83.
Gamma-ray transitions from the bombardment of 64Ni by 16O up to 81 Me V were studied in a variety of experiments. Four transitions in coincidence with four previously known transitions in 74Se were discovered. Information on energies, angular distributions, intensities multiplicities and lifetimes is given for these transitions. Excitation functions for this and several other channels are presented. Statistical calculations are in satisfactory agreement with experiment.  相似文献   
84.
Recent behavior experiments have demonstrated that paddlefish can make use of stochastic resonance while feeding on Daphnia plankton. Here we calculate the information content of the noisy Daphnia signal at the paddlefish rostrum using an exact statistical treatment of threshold stochastic resonance as a minimal neural model. These calculations compare well with experimentally obtained data on paddlefish strikes at Daphnia prey.  相似文献   
85.
Yakovlev  E. V.  Markov  A. B.  Shepel  D. A.  Petrov  V. I.  Neiman  A. A. 《Russian Physics Journal》2021,63(10):1804-1809
Russian Physics Journal - The paper presents the adhesive strength measurements of the Ni–Cu surface alloy formed on a copper substrate at a different thickness of the transition layer. The...  相似文献   
86.
87.
Zykov  V. M.  Neiman  D. A. 《Russian Physics Journal》2018,60(12):2201-2208
Russian Physics Journal - A physico-mathematical model of the processes of radiation-induced charging of dielectric materials with open surfaces, irradiated with monoenergetic electrons in the...  相似文献   
88.
Perovskite phases Ba3In2ZrO8 and Ba4In2Zr2O11 with the nominal concentration of structural oxygen vacancies 1/9 and 1/12, respectively, were synthesized by solid-phase and solution methods. X-ray diffraction showed cubic symmetry of both phases with the unit cell parameter a = 0.4193(2) and 0.4204(3) nm, respectively. The absence of superstructural lines resulted in the conclusion on statistical arrangement of oxygen vacancies. Thermogravimetry and mass spectrometry proved that both phases can reversibly absorb water from gas phase (pH2O = 2 × 10−2 atm) with observed correlation between the concentration of oxygen vacancies and amount of absorbed water. The total water amount was up to 0.9 mol per formula unit or, if recalculated for perovskite unit ABO3, 0.3 and 0.23 mol H2O, respectively. The temperature curves of coductivity in the atmosphere with various partial water vapor pressures (pH2O = 3 × 10−5 and 2 × 10−2 atm) showed significantly higher conductivity and lower activation energy (0.52 eV) in humid atmosphere due to proton transfer. The proton conductivity is up to 5 × 10−4 Ohm−1 cm−1 at 300°C for Ba3In2ZrO8 specimen. IR spectrometry showed that protons in the structure exist primarily in OH-groups.  相似文献   
89.
We compare data on the reciprocal electrosurface transfer (EST) of WO3 and MWO4 components through WO3|MWO4 eutectic heterointerfaces using MWO4 (M = Ca, Sr, Ba) samples prepared by standard ceramic technology (CER) and nitrate-organic technology (N/O); these samples considerably differ in both the grain size of precursor powders and the grain size of sintered ceramics. When an electric field is applied, the interpenetration of WO3 and MWO4 components occurs though WO3|MWO4 (M = Ca, Sr, Ba) heterointerfaces. The general (−)WO3 ↔ MWO4 (+) intermigration pattern in the cells is not influenced by tungstate preparation technology. However, interpenetration rates are far greater for MW4N/O. The transport properties of {MWO4 · xWO3} two-phase eutectic metacomposites manufactured by both technologies were studied. Tungstate and composite manufacturing technologies have no radical influence on the electric properties (overall and partial conductivity, transference numbers) of the samples, only changing conductivity versus concentration relationships. Our data well fit the model of formation of a nonautonomous electrolytic interphase.  相似文献   
90.
We present a method that significantly enhances the robustness of (automated) NMR structure determination by allowing the NOE data corresponding to unassigned NMR resonances to be used directly in the calculations. The unassigned resonances are represented by additional atoms or groups of atoms that have no interaction with the regular protein atoms except through distance restraints. These so-called "proxy" residues can be used to generate NOE-based distance restraints in a similar fashion as for the assigned part of the protein. If sufficient NOE information is available, the restraints are expected to place the proxies at positions close to the correct atoms for the unassigned resonance, which can facilitate subsequent assignment. Convergence can be further improved by supplying additional information about the possible identities of the unassigned resonances. We have implemented this approach in the widely used automated assignment and structure calculation protocols ARIA and CANDID. We find that it significantly increases the robustness of structure calculations with regard to missing assignments and yields structures of higher quality. Our approach is still able to find correctly folded structures with up to 30% randomly missing resonance assignments, and even when only backbone and beta resonances are present! This should be of significant value to NMR-based structural proteomics initiatives.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号