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61.
M. Valkeapää Y. Katsumata T. Motohashi R.S. Liu H. Yamauchi 《Journal of solid state chemistry》2007,180(5):1608-1615
A comparative study on the oxidation and charge compensation in the AxCoO2−δ systems, A=Na (x=0.75, 0.47, 0.36, 0.12) and Li (x=1, 0.49, 0.05), using X-ray absorption spectroscopy at O 1s and Co 2p edges is reported. Both the O 1s and Co 2p XANES results show that upon removal of alkali metal from AxCoO2−δ the valence of cobalt increases more in LixCoO2−δ than in NaxCoO2−δ. In addition, the data of O 1s XANES indicate that charge compensation by oxygen is more pronounced in NaxCoO2−δ than in LixCoO2−δ. 相似文献
62.
J. Zsakó 《Journal of Thermal Analysis and Calorimetry》1996,46(6):1845-1864
Four many curves methods, viz. calculation techniques based on Eqs (30), (31), (34) and (36), respectively, for deriving kinetic parameters from several TG curves recorded with different heating rates are tested on two sets of theoretical TG curves. The maximum reaction rate temperature and conversion, as well as the approximate formulae used for their calculation are discussed. Some aspects of the kinetic compensation effect are analysed. The final conclusion is that the use of the many curves methods is not reasonable. 相似文献
63.
It follows from an analysis of the error levels of TG evaluation methods that it is a conceptual error to disregard the analogies
of mass, energy and momentum streams of subordinate partial processes. This error is bypassed by means of the introduced method
of dimensionless analysis and by determining the characteristic, constants-like data of thermal processes by using the measured
data directly. These methods are very suitable for increasing the consistency of the calculated results by seeking for similarity,
even in comparisons of measurements made under very different conditions and for emphasizing the differences too, quantitatively.
With this new interpretation of TG processes, the idea of the kinetic compensation effect becomes only a consequence of the
discussed conceptual error.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
64.
Guo X Shuang S Wang X Dong C Pan J Aboul-Enein HY 《Biomedical chromatography : BMC》2004,18(8):559-563
The interaction of rutin and venoruton (troxerutin), with alpha-, beta- and gamma-cyclodextrin (CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and methyl-beta-cyclodextrin (M-beta-CD) was investigated by reversed-phase thin layer chromatography on polyamide plates. A mobile phase consisted of NH(4)OH; NH(4)Cl buffer solution containing various CD concentrations (pH = 9.7, 20 degrees C) was used as mobile phase. The equilibrium constants (K(f)) and the retention factor (R(f)) were determined and used to study the inclusion process. The in fluence of CDs on the solubility of rutin and venoruton was characterized by R(M) values and the increasing hydrophilicity of drugs. The results show that the inclusion capacity of cyclodextrins follows the order HP-beta-CD > M-beta-CD > beta-CD > gamma-CD, and rutin is more easily included by the studied cyclodextrins than venoruton. In addition, the thermodynamic parameters (Delta H, Delta S) for the formation of complexes were obtained from the van't Hoff equation, displaying the enthalpy-entropy compensation effect. 相似文献
65.
Riccardo Baron Daniel Trzesniak Alex H de Vries Andreas Elsener Siewert J Marrink Wilfred F van Gunsteren 《Chemphyschem》2007,8(3):452-461
Thermodynamic data are often used to calibrate or test amomic-level (AL) force fields for molecular dynamics (MD) simulations. In contrast, the majority of coarse-grained (CG) force fields do not rely extensively on thermodynamic quantities. Recently, a CG force field for lipids, hydrocarbons, ions, and water, in which approximately four non-hydrogen atoms are mapped onto one interaction site, has been proposed and applied to study various aspects of lipid systems. To date, no extensive investigation of its capability to describe salvation thermodynamics has been undertaken. In the present study, a detailed picture of vaporization, solvation, and phase-partitioning thermodynamics for liquid hydrocarbons and water was obtained at CG and AL resolutions, in order to compare the two types or models and evaluate their ability to describe thermodynamic properties in the temperature range between 263 and 343 K. Both CG and AL models capture the experimental dependence of the thermodynamic properties on the temperature, albeit a systematically weaker dependence is found for the CG model. Moreover, deviations are found for solvation thermodynamics and for the corresponding enthalpy-entropy compensation for the CG model. Particularly water/oil repulsion seems to be overestimated. However, the results suggest that the thermodynamic properties considered should be reproducible by a CG model provided it is reparametrized on the basis of these liquid-phase properties. 相似文献
66.
基于参考光栅的光纤光栅应变传感器温度补偿 总被引:6,自引:8,他引:6
为解决光纤布拉格光栅(FBG)应变测量时的应变、温度交叉敏感问题,利用FBG便于构成传感网络的优点,将温度补偿参考FBG与应变测量FBG串联在一路光纤上,根据2只FBG布拉格波长相对漂移获得被测结构应变。双FBG波长相对漂移对温度的灵敏度仅为0.12pm/℃,较好地实现FBG应变测量的温度补偿。参考FBG法原理简单,可操作性强,为FBG应变传感器的实际工程应用奠定了基础。 相似文献
67.
68.
69.
A nonvolatile memory based on an organic thin-film transistor (OTFT) with a biopolymer of DNA-cetyltrimethylammonium chloride (DNA-CTMA) acting as the gate dielectric layer was fabricated. The transfer characteristics of the device prepared by both DNA alone and DNA-CTMA showed a very large and stable hysteresis. In order to analyze the memory mechanism, the temperature dependence of the transfer characteristics, electric conductivity, differential scanning calorimetry (DSC), thermally stimulated depolarization current (TSDC) as well as the dielectric property of the DNA-CTMA film have been investigated. As a result, the quasi-ferroelectric polarization originating from the alignment of the intrinsic dipole moment inside the DNA-CTMA complex was identified as the main source of hysteresis in the lower temperature region. 相似文献
70.