全文获取类型
收费全文 | 7840篇 |
免费 | 186篇 |
国内免费 | 4篇 |
专业分类
化学 | 5162篇 |
晶体学 | 36篇 |
力学 | 242篇 |
数学 | 1018篇 |
物理学 | 1572篇 |
出版年
2022年 | 51篇 |
2021年 | 69篇 |
2020年 | 97篇 |
2019年 | 97篇 |
2018年 | 112篇 |
2017年 | 73篇 |
2016年 | 161篇 |
2015年 | 193篇 |
2014年 | 184篇 |
2013年 | 373篇 |
2012年 | 450篇 |
2011年 | 437篇 |
2010年 | 296篇 |
2009年 | 205篇 |
2008年 | 454篇 |
2007年 | 416篇 |
2006年 | 385篇 |
2005年 | 355篇 |
2004年 | 327篇 |
2003年 | 302篇 |
2002年 | 253篇 |
2001年 | 158篇 |
2000年 | 167篇 |
1999年 | 77篇 |
1998年 | 106篇 |
1997年 | 93篇 |
1996年 | 119篇 |
1995年 | 64篇 |
1994年 | 83篇 |
1993年 | 81篇 |
1992年 | 69篇 |
1991年 | 53篇 |
1990年 | 64篇 |
1989年 | 53篇 |
1988年 | 67篇 |
1987年 | 43篇 |
1986年 | 58篇 |
1985年 | 86篇 |
1984年 | 88篇 |
1983年 | 51篇 |
1982年 | 68篇 |
1981年 | 88篇 |
1980年 | 79篇 |
1979年 | 65篇 |
1978年 | 74篇 |
1977年 | 67篇 |
1976年 | 76篇 |
1975年 | 50篇 |
1974年 | 35篇 |
1973年 | 39篇 |
排序方式: 共有8030条查询结果,搜索用时 15 毫秒
141.
Daniel S. Covita Dimitrios F. Anagnostopoulos Hermann Fuhrmann Hubert Gorke Detlev Gotta Alexander Gruber Albert Hirtl Tomoichi Ishiwatari Paul Indelicato Thomas S. Jensen Eric-Olivier Le Bigot Valeri E. Markushin Michael Nekipelov Vladimir N. Pomerantsev Vladimir P. Popov Joaquim M. F. dos Santos Philipp Schmid Leopold M. Simons Marian Theisen Martino Trassinelli Joao F. C. A. Veloso Johann Zmeskal 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2018,72(4):72
142.
143.
144.
By means of ab initio calculation based on density-functional theory (DFT), we have investigated the electronic and optical properties of single layer MoSe2 under chemical doping by various groups, such as ?H, ?OH, ?NH2 and ?CH3. This work is generalized for all polymorph 1H, 1T, 1T′ and the new investigated phase 1T″. We found that all those functional groups (FG) bonded covalently to the chalcogen atom (Se). The evaluation of adsorption energy shows that the hydrogen atom binds more strongly than other functional groups in particular with the T phase. Furthermore, the attachment of functional groups to T-MoSe2 leads to dramatic changes to the structure stability and the optoelectronic properties of the material by tuning its band gap from metallic to a semiconductor. Also, we found that the band gap is strongly depending on the type and the densities of dopants. 相似文献
145.
A CE instrument that can be assembled from commercially available components with minimal construction effort is described. Except for the electronic control circuitry no specially made parts are required. It is based on a flexible design of microfluidic, electropneumatic, and electronic sections and different configurations can easily be implemented. Automated injection into the capillary is performed hydrodynamically by the application of a pressure for a controlled length of time. The performance of the device was tested with a contactless conductivity detector by separating different metal ions. In addition, nine metal cations related to the quality of honey were separated in 2.3 min and four honey samples were analysed quantitatively to demonstrate the applicability of the method. 相似文献
146.
Model reduction techniques such as Proper Generalized Decomposition (PGD) are decision-making tools that are about to revolutionize many domains. Unfortunately, their computation is still problematic for problems involving many parameters, for which one has to face the “curse of dimensionality”. An answer to this challenge is given in solid mechanics by the so-called “parameter-multiscale PGD”, which is based on Saint-Venant's principle. In this article, a model problem composed of up to a thousand parameters is presented, showing that the method is able to overcome the “curse of dimensionality”. 相似文献
147.
We propose a new Monte Carlo method to efficiently sample a multimodal distribution (known up to a normalization constant). We consider a generalization of the discrete-time Self Healing Umbrella Sampling method, which can also be seen as a generalization of well-tempered metadynamics. The dynamics is based on an adaptive importance technique. The importance function relies on the weights (namely the relative probabilities) of disjoint sets which form a partition of the space. These weights are unknown but are learnt on the fly yielding an adaptive algorithm. In the context of computational statistical physics, the logarithm of these weights is, up to an additive constant, the free-energy, and the discrete valued function defining the partition is called the collective variable. The algorithm falls into the general class of Wang–Landau type methods, and is a generalization of the original Self Healing Umbrella Sampling method in two ways: (i) the updating strategy leads to a larger penalization strength of already visited sets in order to escape more quickly from metastable states, and (ii) the target distribution is biased using only a fraction of the free-energy, in order to increase the effective sample size and reduce the variance of importance sampling estimators. We prove the convergence of the algorithm and analyze numerically its efficiency on a toy example. 相似文献
148.
149.
D. Drijard H. G. Fischer W. Geist P. G. Innocenti V. Korbel A. Minten A. Norton S. Stein O. Ullaland H. D. Wahl G. Fontaine C. Ghesquière G. Sajot P. Hanke W. Hofmann M. Panter K. Rauschnabel J. Spengler D. Wegener H. Frehse M. Heiden E. E. Kluge A. Putzer M. Della Negra D. Linglin R. Gokieli R. Sosnowski 《Zeitschrift fur Physik C Particles and Fields》1981,9(4):293-303
Inclusive production of ?0,f, andg 0 mesons and ofK s 0 ,K *0 (892), ? andK *0(1430)mesons has been measured at <y>~2.6 and <p T >~1.1 GeV/c in proton-proton interactions at \(\sqrt s = 52.5\) GeV. The negative particle from the two-body decays of these resonances were identified by a threshold Cerenkov counter and used for triggering. Starting from the measured differential cross section, total inclusive cross sections for the vector and tensor mesons were determined using various parametrizations for they andp T dependence of the differential cross section. The experimental results are discussed in the framework of production models based on the parton picture. The strangeness suppresion factor λ=(0.30±0.10) due toSU(3) symmetry breaking of the quark sea is derived. 相似文献
150.
LetA be an abelian variety defined over a number fieldK. LetL be a finite Galois extension ofK with Galois groupG and let III(A/K) and III(A/L) denote, respectively, the Tate-Shafarevich groups ofA overK and ofA overL. Assuming these groups are finite, we compute [III(A/L)
G
]/[III(A/K)] and [III(A/K)]/[N(III(A/L))], where [X] is the order of a finite abelian groupX. Especially, whenL is a quadratic extension ofK, we derive a simple formula relating [III(A/L)], [III(A/K)], and [III(A
x/K)] whereA
x is the twist ofA by the non-trivial characterχ ofG. 相似文献