全文获取类型
收费全文 | 3147篇 |
免费 | 95篇 |
国内免费 | 13篇 |
专业分类
化学 | 1994篇 |
晶体学 | 23篇 |
力学 | 85篇 |
数学 | 409篇 |
物理学 | 744篇 |
出版年
2023年 | 10篇 |
2022年 | 32篇 |
2021年 | 79篇 |
2020年 | 69篇 |
2019年 | 89篇 |
2018年 | 84篇 |
2017年 | 94篇 |
2016年 | 131篇 |
2015年 | 101篇 |
2014年 | 91篇 |
2013年 | 182篇 |
2012年 | 177篇 |
2011年 | 245篇 |
2010年 | 150篇 |
2009年 | 138篇 |
2008年 | 180篇 |
2007年 | 192篇 |
2006年 | 224篇 |
2005年 | 177篇 |
2004年 | 115篇 |
2003年 | 104篇 |
2002年 | 98篇 |
2001年 | 52篇 |
2000年 | 45篇 |
1999年 | 39篇 |
1998年 | 29篇 |
1997年 | 34篇 |
1996年 | 27篇 |
1995年 | 21篇 |
1994年 | 19篇 |
1993年 | 20篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 19篇 |
1989年 | 8篇 |
1988年 | 12篇 |
1987年 | 11篇 |
1986年 | 7篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 15篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1977年 | 9篇 |
1972年 | 3篇 |
1969年 | 8篇 |
1968年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有3255条查询结果,搜索用时 46 毫秒
1.
Vyacheslav V. Sentyurin Oleg A. Levitskiy Tatiana V. Magdesieva 《Current Opinion in Electrochemistry》2020
This mini-review highlights key structural features that should be taken into account when creating ambipolar redox-active closed-shell metal-free molecules. This type of compound is strongly required for the fabrication of all-organic ‘poleless’ batteries and semiconductors. The suggested strategies aimed at stabilization of both oxidized (cationic) and reduced (anionic) redox-states are based on the comprehensive analysis of the most successful structures taken from the recent publications. 相似文献
2.
3.
4.
Enrique Fernández-Cara Sergio Guerrero Oleg Yurievich Imanuvilov Jean-Pierre Puel 《Comptes Rendus Mathematique》2004,338(5):375-380
This Note deals with the controllability of Stokes and Navier–Stokes systems with distributed controls with support in possibly small subdomains. We first present a new global Carleman inequality for the solutions to Stokes-like systems that leads to the null controllability at any time T>0. Then, we present a local result concerning exact controllability to trajectories of the Navier–Stokes system. To cite this article: E. Fernández-Cara et al., C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
5.
Oleg Palumbíny 《Czechoslovak Mathematical Journal》2003,53(2):467-477
The paper deals with oscillation criteria of fourth order linear differential equations with quasi-derivatives. 相似文献
6.
V. D. Kulikov 《Technical Physics》2004,49(10):1368-1374
The flow of the conduction current in a metal-insulator-metal structure under X-ray and optical excitation is considered.
Accumulation of positive charge at the negative electrode in the KBr and CsI crystals is studied. The method of discharge
currents after the X-ray and optical excitation is suggested for estimation of the near-surface charge. It is shown that the
values of charge transported by the conduction current and those determined from the measured discharge-current signal are
in satisfactory agreement. The lifetimes of near-surface charges of holes and anionic vacancies and the values of the electric-field
strength at the metal-insulator interface are estimated. It is assumed that electroneutrality of the sample is established
owing to the motion of electrons from the surface into the bulk over dislocations. 相似文献
7.
8.
Panos M. Pardalos Wanpracha Chaovalitwongse Leonidas D. Iasemidis J. Chris Sackellares Deng-Shan Shiau Paul R. Carney Oleg A. Prokopyev Vitaliy A. Yatsenko 《Mathematical Programming》2004,101(2):365-385
There is growing evidence that temporal lobe seizures are preceded by a preictal transition, characterized by a gradual dynamical change from asymptomatic interictal state to seizure. We herein report the first prospective analysis of the online automated algorithm for detecting the preictal transition in ongoing EEG signals. Such, the algorithm constitutes a seizure warning system. The algorithm estimates STLmax, a measure of the order or disorder of the signal, of EEG signals recorded from individual electrode sites. The optimization techniques were employed to select critical brain electrode sites that exhibit the preictal transition for the warning of epileptic seizures. Specifically, a quadratically constrained quadratic 0-1 programming problem is formulated to identify critical electrode sites. The automated seizure warning algorithm was tested in continuous, long-term EEG recordings obtained from 5 patients with temporal lobe epilepsy. For individual patient, we use the first half of seizures to train the parameter settings, which is evaluated by ROC (Receiver Operating Characteristic) curve analysis. With the best parameter setting, the algorithm applied to all cases predicted an average of 91.7% of seizures with an average false prediction rate of 0.196 per hour. These results indicate that it may be possible to develop automated seizure warning devices for diagnostic and therapeutic purposes.Mathematics Subject Classification (1991):20E28, 20G40, 20C20 相似文献
9.
Oleg Borodin 《Combinatorica》1993,13(1):121-125
The weight of an edge in a graph is the sum of the degrees of its end-vertices. It is proved that in each 3-polytope there exists either an edge of weight at most 13 for which both incident faces are triangles, or an edge of weight at most 10 which is incident with a triangle, or else an edge of weight at most 8. All the bounds 13, 10, and 8 are sharp and attained independently of each other. 相似文献
10.
Yu. D. Perfiliev V. S. Rusakov L. A. Kulikov A. A. Kamnev K. Alkhatib 《Hyperfine Interactions》2006,167(1-3):881-885
To explain line broadening in emission Mössbauer spectra as compared to the corresponding absorber measurements, the model of trapped electrons has been proposed. Auger electrons (emitted, e.g. after electron capture by 57Co or after the converted isomeric transition of 119mSn), as well as secondary electrons, may be trapped in the proximity to the nucleogenic ion. Electrons captured by lattice traps at different distances from the daughter ion induce an asymmetric distribution of quadrupole splitting in the resulting emission spectra, as shown in a few examples. This model is supported by estimates of quadrupole splitting values which may be caused by such trapped electrons located at specified distances from the nucleogenic atom. 相似文献