全文获取类型
收费全文 | 1944篇 |
免费 | 34篇 |
国内免费 | 118篇 |
专业分类
化学 | 401篇 |
晶体学 | 21篇 |
力学 | 43篇 |
综合类 | 2篇 |
数学 | 566篇 |
物理学 | 595篇 |
综合类 | 468篇 |
出版年
2024年 | 13篇 |
2023年 | 127篇 |
2022年 | 28篇 |
2021年 | 38篇 |
2020年 | 39篇 |
2019年 | 37篇 |
2018年 | 32篇 |
2017年 | 61篇 |
2016年 | 40篇 |
2015年 | 49篇 |
2014年 | 109篇 |
2013年 | 131篇 |
2012年 | 152篇 |
2011年 | 161篇 |
2010年 | 142篇 |
2009年 | 85篇 |
2008年 | 64篇 |
2007年 | 67篇 |
2006年 | 66篇 |
2005年 | 55篇 |
2004年 | 52篇 |
2003年 | 39篇 |
2002年 | 40篇 |
2001年 | 40篇 |
2000年 | 54篇 |
1999年 | 31篇 |
1998年 | 34篇 |
1997年 | 30篇 |
1996年 | 28篇 |
1995年 | 24篇 |
1994年 | 29篇 |
1993年 | 15篇 |
1992年 | 19篇 |
1991年 | 11篇 |
1990年 | 15篇 |
1989年 | 16篇 |
1988年 | 16篇 |
1987年 | 10篇 |
1986年 | 3篇 |
1985年 | 19篇 |
1984年 | 11篇 |
1983年 | 2篇 |
1982年 | 13篇 |
1981年 | 5篇 |
1980年 | 11篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1977年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有2096条查询结果,搜索用时 15 毫秒
11.
Alexandra Shlapentokh 《Compositio Mathematica》2002,132(1):99-120
Let F be a function field of characteristic p > 2, finitely generated over a field C algebraic over a finite field C
p
and such that it has an extension of degree p. Then Hilbert's Tenth Problem is not decidable over F. 相似文献
12.
13.
Summary Oblique propagating magnetohydrodynamic waves with various wave forms and amplitudes are observed both at the Earth's foreshock
and at comets. The possibility of interpreting some observational results in terms of nonlinear evolution of one- and two-dimensional
hydromagnetic waves is investigated. For this purpose both analytical and numerical techniques are employed. It is found that
an initial monochromatic wave changes its polarization giving origin to magnetosonic shocks and rotational discontinuities;
the time evolution of density-magnetic-field correlation is studied, as a function of the plasma parameters and of the propagation
angle. In the two-dimensional case both a transverse instability and a self-focusing effect may take place. Moreover, a two-dimensional
magnetosonic solution is found, in which the density fluctuations are driven by the total pressure fluctuation as in a one-dimensional
simple wave. These theoretical predictions compare well with the features observed in the solar-wind waves.
Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990. 相似文献
14.
Results from Super-Kamiokande-I’s entire 1496 live days of solar neutrino data are presented, including the absolute flux,
energy spectrum, zenith angle (day/night) and seasonal variation. The possibility of MSW and vacuum oscillations is discussed
in light of these results. Results from the first 1289 days of Super-K-I’s atmospheric neutrino analysis are also presented,
including the evidence for νμ →ν
τ oscillations, against νμ → νsterile oscillations, and the current limits on proton decay. Finally, results based on 56 × 1019 protons on target are given for the K2K long-baseline neutrino oscillation experiment. 相似文献
15.
Raj Gandhi Kamales Kar S. Uma Sankar Abhijit Bandyopadhyay Rahul Basu Pijushpani Bhattacharjee Biswajoy Brahmachari Debrupa Chakraborti M. Chaudhury J. Chaudhury Sandhya Choubey E. J. Chun Atri Desmukhya Anindya Datta Gautam Dutta Sukanta Dutta Anjan Giri Sourendu Gupta Srubabati Goswami Namit Mahajan H. S. Mani A. Mukherjee Biswarup Mukhopadhyaya S. N. Nayak M. Randhawa Subhendu Rakshit Asim K. Ray Amitava Raychaudhuri D. P. Roy Probir Roy Suryadeep Roy Shiv Sethi G. Sigl Arunansu Sil N. Nimai Singh Mark Vagins Urjit Yagnik 《Pramana》2003,60(2):405-409
This is the report of neutrino and astroparticle physics working group at WHEPP-7. Discussions and work on CP violation in
long baseline neutrino experiments, ultra high energy neutrinos, supernova neutrinos and water Cerenkov detectors are discussed. 相似文献
16.
17.
E. Kolbe K. Langanke F.-K. Thielemann 《The European Physical Journal A - Hadrons and Nuclei》1998,3(4):389-396
We study the influence of a strange axial vector form factor Gs of the nucleon on the neutrino-induced proton and neutron knockout of 16O. In particular, we calculate how much Gs≠0 might affect the recently proposed signal for supernova νμ and ντ neutrinos in the Superkamiokande detector. We discuss whether Superkamiokande might be able to determine the value of Gs in a hypothetical neutrino-beam experiment. Finally we comment on the possible effect Gs≠0 might have on neutrino-nucleus cross sections in the neutrino-driven wind model for the nuclear r-process.
Received: 30 April 1998 / Revised version: 10 August 1998 相似文献
18.
Optimale Quantisierung 总被引:1,自引:0,他引:1
Peter M. Gruber 《Mathematische Semesterberichte》2002,49(2):227-251
Zusammenfassung. Optimale Quantisierungen oder – damit ?quivalent – minimale Summen von Momenten spielen in mehreren Zweigen der Mathematik
und ihrer Anwendungen eine Rolle. Ausgehend von der Fejes Tóth'schen Ungleichung für Summen von Momenten in der euklidischen
Ebene und einem zugeh?rigen Stabilit?tssatz, werden gewisse Erweiterungen auf normierte R?ume und riemannsche Mannigfaltigkeiten
h?herer Dimension besprochen. Die Ergebnisse werden dann auf Probleme aus folgenden Bereichen angewendet: (i) Datenübertragung,
(ii) Wahrscheinlichkeitstheorie, (iii) numerische Integration, (iv) Approximation konvexer K?rper und (v) isoperimetrische
Probleme.
Eingegangen am 29. Mai 2002 / Angenommen am 8. Juli 2002 相似文献
19.
The density of neutral oxygen atoms in the MESOX set-up, one device of the PROMES-CNRS solar facilities, was determined by a fiber-optics catalytic probe (FOCP). Plasma was created in a flowing air within a quartz tube with the outer diameter of 5 cm by a 2.45 GHz microwave generator with the output power up to 1000 W. The flow of air was varied between 4 and 20 l/h. The O-atom density was found to increase monotonously with the increasing discharge power, and it decreased with the increasing flow rate. The degree of dissociation of oxygen molecules in the plasma column depended largely on the flow rate. At the air flow of 4 l/h it was about 80% but it decreased to about 20% at the flow of 20 l/h. 相似文献
20.
Bhattacharya S Schiavone M Nayak A Bhattacharya SK 《Applied biochemistry and biotechnology》2005,120(3):159-167
Our laboratory has recently developed a device employing immobilized F0F1 adenosine triphosphatase (ATPase) that allows synthesis of adenosine triphosphate (ATP) from adenosine 5′-diphosphate and
inorganic phosphate using solar energy. We present estimates of total solar energy received by Earth’s land area and demonstrate
that its efficient capture may allow conversion of solar energy and storage into bonds of biochemicals using devices harboring
either immobilized ATPase or NADH dehydrogenase. Capture and storage of solar energy into biochemicals may also enable fixation
of CO2 emanating from polluting units. The cofactors ATP and NADH synthesized using solar energy could be used for regeneration
of acceptor d-ribulose-1,5-bisphosphate from 3-phosphoglycerate formed during CO2 fixation. 相似文献