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191.
We have examined the effects of crystallization kinetics of poly(3‐hexylthiophene) and poly[2,5‐bis(3‐hexadecylthiophen‐2‐yl)thieno(3,2‐b)thiophene] on microstructure and charge transport. Rapid crystallization increases the density of tie molecules in polythiophenes. As a consequence, ordered regions are better connected resulting in higher charge carrier mobilities. Our results suggest that controlling the crystallization kinetics might be an important factor for maximizing the charge mobility in semicrystalline polythiophene thin films. 相似文献
192.
193.
J. L. C. Ford Jr. J. Gomez del Campo R. L. Robinson P. H. Stelson S. T. Thornton 《Zeitschrift für Physik A Hadrons and Nuclei》1974,269(2):147-153
States in20Ne were populated by the10B(16O,6Li) reaction, and levels were observed up to 11 MeV in excitation energy. Cross sections were measured at 7° (lab) for bombarding energies from 44.4 to 46 MeV in 400 keV intervals. The reaction appears to be predominantly due to compound nucleus formation, and good agreement was found between the measured cross sections and Hauser-Feshbach calculations, assuming the known spin values of20Ne. 相似文献
194.
Transport in Porous Media - Consolidated drained triaxial tests arise as one of the most exhaustive methods to quantify the strength, volumetric behavior and failure process of rocks. Understanding... 相似文献
195.
In this paper we consider the existence and stability of multi-spike solutions to the fractional Gierer-Meinhardt model with periodic boundary conditions.In particular we rigorously prove the existence of symmetric and asymmetric two-spike solutions using a Lyapunov-Schmidt reduction. The linear stability of thesetwo-spike solutions is then rigorously analyzed and found to be determined by theeigenvalues of a certain $2 × 2$ matrix. Our rigorous results are complemented byformal calculations of $N$-spike solutions using the method of matched asymptoticexpansions. In addition, we explicitly consider examples of one- and two-spikesolutions for which we numerically calculate their relevant existence and stabilitythresholds. By considering a one-spike solution we determine that the introductionof fractional diffusion for the activator or inhibitor will respectively destabilize orstabilize a single spike solution with respect to oscillatory instabilities. Furthermore,when considering two-spike solutions we find that the range of parameter valuesfor which asymmetric two-spike solutions exist and for which symmetric two-spikesolutions are stable with respect to competition instabilities is expanded with the introduction of fractional inhibitor diffusivity. However our calculations indicate thatasymmetric two-spike solutions are always linearly unstable. 相似文献
196.
D. Matthew Sublett Jr Eszter Sendula Hector M. Lamadrid Matthew Steele-MacInnis Georg Spiekermann Robert J. Bodnar 《Journal of Raman spectroscopy : JRS》2021,52(3):750-769
The Raman spectral behavior of N2, CO2, and CH4 in ternary N2–CO2–CH4 mixtures was studied from 22°C to 200°C and 10 to 500 bars. The peak position of N2 in all mixtures is located at lower wavenumbers compared with pure N2 at the same pressure (P)–temperature (T) (PT) conditions. The Fermi diad splitting in CO2 is greater in the pure system than in the mixtures, and the Fermi diad splitting increases in the mixtures as CO2 concentration increases at constant P and T. The peak position of CH4 in the mixtures is shifted to higher wavenumbers compared with pure CH4 at the same PT conditions. However, the relationship between peak position and CH4 mole fraction is more complicated compared with the trends observed with N2 and CO2. The relative order of the peak position isotherms of CH4 and N2 in the mixtures in pressure–peak position space mimics trends in the molar volume of the mixtures in pressure–molar volume space. Relationships between the direction of peak shift of individual components in the mixtures, the relative molar volumes of the mixtures, and the attraction and repulsion forces between molecules are developed. Additionally, the relationship between the peak position of N2 in ternary N2–CO2–CH4 mixtures with pressure is extended to other N2-bearing systems to assess similarities in the Raman spectral behavior of N2 in various systems. 相似文献
197.
D. Matthew Sublett Jr. Eszter Sendula Hector Lamadrid Matthew Steele-MacInnis Georg Spiekermann Robert C. Burruss Robert J. Bodnar 《Journal of Raman spectroscopy : JRS》2020,51(3):555-568
The Raman spectra of pure N2, CO2, and CH4 were analyzed over the range 10 to 500 bars and from −160°C to 200°C (N2), 22°C to 350°C (CO2), and −100°C to 450°C (CH4). At constant temperature, Raman peak position, including the more intense CO2 peak (ν+), decreases (shifts to lower wave number) with increasing pressure for all three gases over the entire pressure and temperature (PT) range studied. At constant pressure, the peak position for CO2 and CH4 increases (shifts to higher wave number) with increasing temperature over the entire PT range studied. In contrast, N2 first shows an increase in peak position with increasing temperature at constant pressure, followed by a decrease in peak position with increasing temperature. The inflection temperature at which the trend reverses for N2 is located between 0°C and 50°C at pressures above ~50 bars and is pressure dependent. Below ~50 bars, the inflection temperature was observed as low as −120°C. The shifts in Raman peak positions with PT are related to relative density changes, which reflect changes in intermolecular attraction and repulsion. A conceptual model relating the Raman spectral properties of N2, CO2, and CH4 to relative density (volume) changes and attractive and repulsive forces is presented here. Additionally, reduced temperature-dependent densimeters and barometers are presented for each pure component over the respective PT ranges. The Raman spectral behavior of the pure gases as a function of temperature and pressure is assessed to provide a framework for understanding the behavior of each component in multicomponent N2-CO2-CH4 gas systems in a future study. 相似文献
198.
Hector Castro-Abril Jónathan Heras Jesús del Barrio Laura Paz Clara Alcaine Marina Pérez Aliácar Diego Garzón-Alvarado Manuel Doblaré Ignacio Ochoa 《Macromolecular bioscience》2023,23(10):2300108
Mechanical interactions between cells and their microenvironment play an important role in determining cell fate, which is particularly relevant in metastasis, a process where cells invade tissue matrices with different mechanical properties. In vitro, type I collagen hydrogels have been commonly used for modeling the microenvironment due to its ubiquity in the human body. In this work, the combined influence of the stiffness of these hydrogels and their ultrastructure on the migration patterns of HCT-116 and HT-29 spheroids are analyzed. For this, six different types of pure type I collagen hydrogels by changing the collagen concentration and the gelation temperature are prepared. The stiffness of each sample is measured and its ultrastructure is characterized. Cell migration studies are then performed by seeding the spheroids in three different spatial conditions. It is shown that changes in the aforementioned parameters lead to differences in the mechanical stiffness of the matrices as well as the ultrastructure. These differences, in turn, lead to distinct cell migration patterns of HCT-116 and HT-29 spheroids in either of the spatial conditions tested. Based on these results, it is concluded that the stiffness and the ultrastructural organization of the matrix can actively modulate cell migration behavior in colorectal cancer spheroids. 相似文献
199.
J. Ferreira da Silva M. A. P. P. L. Frey Ramos
D. Gignoux
J. C. Gomez Sal
《Journal of magnetism and magnetic materials》1989,80(2-3):149-152Specific heat measurements performed in the temperature range 1.5 to 30 K in the compounds CeNixPt1 - x with x = 0.5, 0.8 and 0.95 are presented. The analysis of the magnetic entropy enhances the results obtained previously by magnetic measurements: i) the reduction of the cerium moment due to the Kondo effect; ii) the increase of the importance of the Kondo effect in competition with the RKKY interactions when Pt is replaced by Ni. The variation of γ along the series indicates a maximum around x = 0.9 which corresponds to the magnetic instability. It is worth noting that below Tc in the ferromagnetic compounds, Cmag follows a T
law, characteristic of magnon dispersion. 相似文献
200.
We consider how the Kelvin–Helmholtz instability is affected by an external hyperbolic strain flow. The basic flow being unsteady, the inviscid evolution of perturbations is studied within the framework of a non-normal analysis in which the maximum amplification is computed for any given time. A positive or negative stretching is shown to enhance or reduce, respectively, the instability even for weak stretching rates. To cite this article: T. Gomez, M. Rossi, C. R. Mecanique 331 (2003). 相似文献