全文获取类型
收费全文 | 1086篇 |
免费 | 57篇 |
国内免费 | 1篇 |
专业分类
化学 | 720篇 |
晶体学 | 2篇 |
力学 | 53篇 |
数学 | 153篇 |
物理学 | 216篇 |
出版年
2024年 | 4篇 |
2023年 | 9篇 |
2022年 | 41篇 |
2021年 | 50篇 |
2020年 | 39篇 |
2019年 | 27篇 |
2018年 | 28篇 |
2017年 | 20篇 |
2016年 | 71篇 |
2015年 | 40篇 |
2014年 | 42篇 |
2013年 | 72篇 |
2012年 | 83篇 |
2011年 | 115篇 |
2010年 | 57篇 |
2009年 | 37篇 |
2008年 | 55篇 |
2007年 | 63篇 |
2006年 | 57篇 |
2005年 | 59篇 |
2004年 | 31篇 |
2003年 | 33篇 |
2002年 | 24篇 |
2001年 | 6篇 |
2000年 | 12篇 |
1999年 | 6篇 |
1997年 | 2篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1987年 | 2篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1961年 | 1篇 |
1948年 | 1篇 |
1938年 | 1篇 |
1937年 | 1篇 |
1918年 | 1篇 |
1916年 | 1篇 |
排序方式: 共有1144条查询结果,搜索用时 15 毫秒
81.
R. Bernabei P. Belli F. Montecchia F. Nozzoli F. Cappella A. Incicchitti D. Prosperi R. Cerulli C.J. Dai H.L. He H.H. Kuang J.M. Ma X.H. Ma X.D. Sheng Z.P. Ye R.G. Wang Y.J. Zhang 《The European Physical Journal C - Particles and Fields》2008,53(2):205-213
The channeling effect of low energy ions along the crystallographic axes and planes of NaI(Tl) crystals is discussed in the
framework of corollary investigations on WIMP dark matter candidates. In fact, the modeling of this existing effect implies
a more complex evaluation of the luminosity yield for low energy recoiling Na and I ions. In the present paper related phenomenological
arguments are developed and possible implications are discussed at some extent.
PACS 95.35.+d 相似文献
82.
83.
We prove that in a family of projective threefolds defined over an algebraically closed field, the locus of rational fibers is a countable union of closed subsets of the locus of separably rationally connected fibers. When the ground field has characteristic zero, this implies that the locus of rational fibers in a smooth family of projective threefolds is the union of at most countably many closed subfamilies. 相似文献
84.
Antonio Cassano Alberto Manganaro Todd Martin Douglas Young Nadège Piclin Marco Pintore Davide Bigoni Emilio Benfenati 《Chemistry Central journal》2010,4(Z1):S4
Background
The new REACH legislation requires assessment of a large number of chemicals in the European market for several endpoints. Developmental toxicity is one of the most difficult endpoints to assess, on account of the complexity, length and costs of experiments. Following the encouragement of QSAR (in silico) methods provided in the REACH itself, the CAESAR project has developed several models.Results
Two QSAR models for developmental toxicity have been developed, using different statistical/mathematical methods. Both models performed well. The first makes a classification based on a random forest algorithm, while the second is based on an adaptive fuzzy partition algorithm. The first model has been implemented and inserted into the CAESAR on-line application, which is java-based software that allows everyone to freely use the models.Conclusions
The CAESAR QSAR models have been developed with the aim to minimize false negatives in order to make them more usable for REACH. The CAESAR on-line application ensures that both industry and regulators can easily access and use the developmental toxicity model (as well as the models for the other four endpoints).85.
Fabio Gosetti Ugo Chiuminatto Davide Zampieri Eleonora Mazzucco Emilio Marengo Maria Carla Gennaro 《Journal of chromatography. A》2010,1217(20):3427-3434
The study investigates the natural photodegradation pathway of mono-chloroanilines in river waters, with the aim to identify the predominant photoproducts formed. At this purpose a new sensitive on-line SPE HPLC–MS/MS method has been developed with LOQ values equal or lower than the legal threshold concentration levels allowed for mono-chloroanilines in waters. The degradation processes of o-, m- and p-chloroaniline have been investigated subjecting their solutions, prepared both in ultrapure and in river water, to sun light irradiation simulated by a solar box system. The SPE HPLC–MS/MS methodology allowed to evaluate the degradation kinetics, to identify the predominant photodegradation products and to propose the chemical structures. Two photoproducts (aniline and 3-aminophenol), for which standards are available, have also been quantified. 相似文献
86.
Triggering rogue waves in opposing currents 总被引:1,自引:0,他引:1
We show that rogue waves can be triggered naturally when a stable wave train enters a region of an opposing current flow. We demonstrate that the maximum amplitude of the rogue wave depends on the ratio between the current velocity U(0) and the wave group velocity c(g). We also reveal that an opposing current can force the development of rogue waves in random wave fields, resulting in a substantial change of the statistical properties of the surface elevation. The present results can be directly adopted in any field of physics in which the focusing nonlinear Schr?dinger equation with nonconstant coefficient is applicable. In particular, nonlinear optics laboratory experiments are natural candidates for verifying experimentally our results. 相似文献
87.
Cribier M Fechner M Lasserre T Letourneau A Lhuillier D Mention G Franco D Kornoukhov V Schönert S 《Physical review letters》2011,107(20):201801
Several observed anomalies in neutrino oscillation data can be explained by a hypothetical fourth neutrino separated from the three standard neutrinos by a squared mass difference of a few eV(2). We show that this hypothesis can be tested with a PBq (ten kilocurie scale) (144)Ce or (106)Ru antineutrino beta source deployed at the center of a large low background liquid scintillator detector. In particular, the compact size of such a source could yield an energy-dependent oscillating pattern in event spatial distribution that would unambiguously determine neutrino mass differences and mixing angles. 相似文献
88.
k-core percolation is an extension of the concept of classical percolation and is particularly relevant to understanding the resilience of complex networks under random damage. A new analytical formalism has been recently proposed to deal with heterogeneous k-cores, where each vertex is assigned a local threshold k(i). In this Letter we identify a binary mixture of heterogeneous k-cores which exhibits a tricritical point. We investigate the new scaling scenario and calculate the relevant critical exponents, by analytical and computational methods, for Erd?s-Rényi networks and 2D square lattices. 相似文献
89.
We investigate how models for neutrino–nucleus cross sections based on different assumptions for the nuclear dynamics affect the forecasted sensitivities to neutrino oscillation parameters at future neutrino facilities. We limit ourselves to the quasi-elastic regime, where the neutrino cross sections can be evaluated with less uncertainties, and discuss the sensitivity reach to θ13 and δ at a prototype low-γ β-beam, mostly sensitive to the quasi-elastic regime. 相似文献
90.
R. Bernabei P. Belli F. Montecchia W. Di Nicolantonio G. Ignesti A. Incicchitti D. Prosperi C. J. Dai L. K. Ding H. H. Kuang J. M. Ma 《Physics letters. [Part B]》1999,450(4):40
The results achieved with a statistics of 14962 kg·day, collected with the large mass highly radiopure DAMA NaI(Tl) set-up, are described and investigated in terms of WIMP annual modulation signature. A maximum likelihood analysis of these data, combined with the statistics of 4549 kg·day previously published (total statistics of 19511 kg·day), favours the hypothesis of presence of an annual modulation at 99.6% C.L. 相似文献