全文获取类型
收费全文 | 2806篇 |
免费 | 127篇 |
国内免费 | 4篇 |
专业分类
化学 | 2177篇 |
晶体学 | 17篇 |
力学 | 36篇 |
数学 | 238篇 |
物理学 | 469篇 |
出版年
2023年 | 34篇 |
2022年 | 104篇 |
2021年 | 119篇 |
2020年 | 74篇 |
2019年 | 67篇 |
2018年 | 68篇 |
2017年 | 45篇 |
2016年 | 116篇 |
2015年 | 83篇 |
2014年 | 104篇 |
2013年 | 167篇 |
2012年 | 179篇 |
2011年 | 182篇 |
2010年 | 119篇 |
2009年 | 94篇 |
2008年 | 200篇 |
2007年 | 155篇 |
2006年 | 151篇 |
2005年 | 150篇 |
2004年 | 117篇 |
2003年 | 88篇 |
2002年 | 79篇 |
2001年 | 52篇 |
2000年 | 49篇 |
1999年 | 35篇 |
1998年 | 33篇 |
1997年 | 24篇 |
1996年 | 33篇 |
1995年 | 11篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 22篇 |
1991年 | 10篇 |
1990年 | 20篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1975年 | 5篇 |
1973年 | 3篇 |
1972年 | 4篇 |
排序方式: 共有2937条查询结果,搜索用时 15 毫秒
1.
General Relativity and Gravitation - In previous work, we established theoretical results concerning the effect of matter shells surrounding a gravitational wave (GW) source, and we now apply these... 相似文献
2.
Prof. Dr. Francisco Melo Leonardo Caballero Esteban Zamorano Natalia Ventura Camilo Navarro Irving Doll Prof. Dr. Pedro Zamorano Prof. Dr. Alberto Cornejo 《Chemphyschem》2021,22(6):526-532
Parkinson's disease is a neurodegenerative disorder involving a functional protein, α-synuclein, whose primary function is related to vesicle trafficking. However, α-synuclein is prone to form aggregates, and these inclusions, known as Lewy bodies, are the hallmark of Parkinson's disease. α-synuclein can alter its conformation and acquire aggregating capacity, forming aggregates containing β-sheets. This protein's pathogenic importance is based on its ability to form oligomers that impair synaptic transmission and neuronal function by increasing membrane permeability and altering homeostasis, generating a deleterious effect over cells. First, we establish that oligomers interfere with the mechanical properties of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) membrane, as demonstrated by nanoindentation curves. In contrast, nanoindentation revealed that the α-synuclein monomer's presence leads to a much more resistant lipid bilayer. Moreover, the oligomers’ interaction with cell membranes can promote lactate dehydrogenase (LDH) release, suggesting the activation of cytotoxic events. 相似文献
3.
4.
Natalia L. Calvo Sebastian O. SimonettiRubén M. Maggio Teodoro S. Kaufman 《Analytica chimica acta》2015
Exposure of cimetidine (CIM) to dry heat (160–180 °C) afforded, upon cooling, a glassy solid containing new and hitherto unknown products. The kinetics of this process was studied by a second order chemometrics-assisted multi-spectroscopic approach. Proton and carbon-13 nuclear magnetic resonance (NMR), as well as ultraviolet and infrared spectroscopic data were jointly used, whereas multivariate curve resolution with alternating least squares (MCR-ALS) was employed as the chemometrics method to extract process information. It was established that drug degradation follows a first order kinetics. 相似文献
5.
The interferometric intensity patterns from a 2D shearing interferometer are shown and discussed. The intensity patterns can be obtained in two different approaches incorporating differential and extended wavefront controlled displacements. The reliable directional sensitivity of this interferometer allows the optimization of the measurement parameters to estimate the wavefront of the intensity patterns by regularization techniques. 相似文献
6.
Formalization for problems of multicriteria decision making under uncertainty is constructed in terms of guaranteed and weak
estimates. A relevant definition of the vector maximinimax value is given. Parameterization and approximation of maximum,
minimax, and maximinimax values based on the inverse logical convolution are suggested. An application for multicommodity
networks is considered.
Received: December 13, 2000 / Accepted: August 21, 2001?Published online May 8, 2002 相似文献
7.
On the basis of the general class of solutions of 6D vacuum Einstein equations and using well-known results of the 6D geometric model of electroweak and gravitational interactions, the variations of fundamental physical constants and their influence on the observed red-shift of galaxies are investigated. By considering the interpretation of extra components of the 6D metric as reproducing the properties of matter in the 4D curved space-time, the effective quantities of matter are obtained. In particular, the states of dust and radiation are shown. The corresponding 5D models were also investigated. 相似文献
8.
The treatment of tertiary esters with triphenylphosphine and iodine under mild conditions gives the most stable alkene in good yield. Formates, acetates and trifluoroacetates were studied. 相似文献
9.
G. Romero L. Alvarez E. Alanís L. Nallim R. Grossi 《Optics and Lasers in Engineering》2003,40(1-2):81-90
Real-time electronic speckle pattern interferometry (ESPI) was used for tuning and visualization of natural frequencies of a trapezoidal plate. The plate was excited to resonant vibration by a sinusoidal acoustical source, which provided a continuous range of audio frequencies. Fringe patterns produced during the time-average recording of the vibrating plate—corresponding to several resonant frequencies—were registered. From these interferograms, calculations of vibrational amplitudes by means of zero-order Bessel functions were performed in some particular cases. The system was also studied analytically. The analytical approach developed is based on the Rayleigh–Ritz method and on the use of non-orthogonal right triangular co-ordinates. The deflection of the plate is approximated by a set of beam characteristic orthogonal polynomials generated by using the Gram–Schmidt procedure. A high degree of correlation between computational analysis and experimental results was observed. 相似文献
10.
G. Baldsiefen H. Hübel W. Korten U. J. van Severen J. A. Cizewski N. H. Medina D. R. Napoli C. Rossi Alvarez G. Lo Bianco S. Signorelli 《Zeitschrift für Physik A Hadrons and Nuclei》1996,355(1):337-338
High-spin states in196Pb have been populated using the reaction170Er(30Si,4n). The previously observed shears bands in this nucleus have been extended and some of their transitions have been reordered. They now form regular bands with band crossings. One of the bands splits into two pathways at high spin. 相似文献