全文获取类型
收费全文 | 628篇 |
免费 | 9篇 |
国内免费 | 3篇 |
专业分类
化学 | 364篇 |
晶体学 | 7篇 |
力学 | 8篇 |
数学 | 99篇 |
物理学 | 162篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 13篇 |
2014年 | 7篇 |
2013年 | 20篇 |
2012年 | 39篇 |
2011年 | 32篇 |
2010年 | 13篇 |
2009年 | 25篇 |
2008年 | 24篇 |
2007年 | 37篇 |
2006年 | 28篇 |
2005年 | 32篇 |
2004年 | 30篇 |
2003年 | 25篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 3篇 |
1998年 | 10篇 |
1997年 | 6篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1974年 | 6篇 |
1973年 | 3篇 |
1966年 | 3篇 |
1934年 | 6篇 |
1887年 | 2篇 |
排序方式: 共有640条查询结果,搜索用时 15 毫秒
61.
G. Dattoli B. Germano M.R. Martinelli P.E. Ricci 《Mathematical and Computer Modelling》2009,50(9-10):1332-1337
We show that the combination of the formalism underlying the principle of monomiality and of methods of an algebraic nature allows the solution of different families of partial differential equations. Here we use different realizations of the Heisenberg–Weyl algebra and show that a Sheffer type realization leads to the extension of the method to finite difference and integro-differential equations. 相似文献
62.
We use the Laguerre-type exponentials, i.e., eigenfunctions of the Laguerre-type derivatives, in order to construct new models for population growth. Relevant modifications of the classical exponential, logistic, and Volterra-Lotka models are investigated. 相似文献
63.
64.
65.
We show that a standard hollow-core fiber (HCF) compressor device can be used to efficiently compress multi-mJ energy laser
pulses down to few-cycle duration, when seeded with linearly chirped, circularly polarized pulses. With this approach, we
routinely generate carrier-envelope phase (CEP)-locked, 1.6 mJ, 4.8 fs pulses using only 3 mJ, 25 fs pulses as the seed. 相似文献
66.
The dominant noises which limit the present sensitivity of the gravitational wave detectors are the thermal noise of the suspended
mirrors and the shot noise. For the third generation of gravitational wave detectors as the Einstein Telescope (ET), the reduction
of the shot noise implies to increase the power stored in the detector at 1 MW level and, at the same time, to compensate
the huge optic distortion due to induced thermal lensing. At low temperature it is possible to reduce both these effects.
However, lowering the temperature of the test masses without injecting vibration noise from the cooling system is a technological
challenge. We review here the thermal noise impact on the ultimate ET sensitivity limit and we discuss possible cryogenic
configurations to cool the mirror. 相似文献
67.
G. Ciasca M. Chiarpotto G. Campi B. Bocca M. Rodio A. Pino A. Ricci N. Poccia C. Rossi A. Alimonti H. Amenitsch P. De Sole A. Bianconi 《Journal of nanoparticle research》2011,13(11):6149-6155
This study investigates the uptake of iron and aluminium by apoferritin. In particular, we provide the first evidence that apoferritin is able to bind in vitro the physiological form of aluminium, Al(OH)4 ?, to reach an Al/Fe atomic ratio of about 0.15. Mass spectrometry analysis shows that the Al content increases linearly as a function of Al concentration in solution. These findings provide a better understanding of the Al uptake in vivo, confirming that the metal content of ferritin depends on the metal bio-availability. 相似文献
68.
Goran Zgrablić Maria Ricci Anna Maria Novello Fulvio Parmigiani 《Photochemistry and photobiology》2010,86(3):507-512
An all-optical experimental technique aimed at measuring photoisomerization quantum yield (ϕ) of the all-trans protonated Schiff base of retinal in solution has been implemented. Upon the increase in the excitation wavelength from 400 to 540 nm a slight increase in ϕ from 0.16 ± 0.03 to 0.20 ± 0.02 is observed in the chromophore dissolved in methanol, whereas the ϕ value of the one dissolved in acetonitrile varies only from 0.22 ± 0.03 (400 nm) to 0.23 ± 0.04 (540 nm). The results suggest that dissipation of the excited-state vibrational energy excess, along with environment-induced modifications of the potential energy surfaces are necessary for an efficient retinal photoisomerization in both solvent and protein environment. 相似文献
69.
L. Vannucci U. Abbondanno M. Bettiolo M. Bruno N. Cindro M. D'Agostino P. M. Milazzo R. A. Ricci G. Vannini 《Zeitschrift für Physik A Hadrons and Nuclei》1994,349(3-4):223-225
Excitation function and angular distributions of the62Ni(58Ni,58Ni)62Ni elastic scattering have been measured at incident58Ni energies from 220.0 to 230.0 MeV in steps of 0.5 MeV. Evidence of two structures was found in the excitation function; a statistical analysis suggests a possible nuclear cluster quasi-molecular nature for these structures. 相似文献
70.
S. Yu. Kun U. Abbondanno M. Bruno N. Cindro M. D’Agostino P. M. Milazzo R. A. Ricci T. Ritz B. A. Robson W. Scheid A. V. Vagov G. Vannini L. Vannucci 《Zeitschrift für Physik A Hadrons and Nuclei》1997,359(2):145-148
Structures of non-statistical character, recently observed in 58 Ni +46 Ti elastic and 58 Ni +62 Ni elastic and inelastic excitation functions, produce damped oscillations in the cross section energy autocorrelation functions. The analysis of these damped oscillations in terms of S-matrix spin and parity decoherence indicates, as a possible interpretation, damping of the coherent rotational motion of the intermediate dinuclear system formed in the reaction. 相似文献