全文获取类型
收费全文 | 3895篇 |
免费 | 150篇 |
国内免费 | 3篇 |
专业分类
化学 | 2310篇 |
晶体学 | 54篇 |
力学 | 166篇 |
数学 | 328篇 |
物理学 | 1190篇 |
出版年
2023年 | 27篇 |
2022年 | 85篇 |
2021年 | 100篇 |
2020年 | 95篇 |
2019年 | 137篇 |
2018年 | 165篇 |
2017年 | 130篇 |
2016年 | 188篇 |
2015年 | 127篇 |
2014年 | 160篇 |
2013年 | 200篇 |
2012年 | 229篇 |
2011年 | 256篇 |
2010年 | 175篇 |
2009年 | 133篇 |
2008年 | 189篇 |
2007年 | 195篇 |
2006年 | 199篇 |
2005年 | 155篇 |
2004年 | 131篇 |
2003年 | 93篇 |
2002年 | 119篇 |
2001年 | 68篇 |
2000年 | 60篇 |
1999年 | 46篇 |
1998年 | 24篇 |
1997年 | 22篇 |
1996年 | 23篇 |
1995年 | 20篇 |
1994年 | 21篇 |
1993年 | 20篇 |
1992年 | 25篇 |
1991年 | 22篇 |
1990年 | 19篇 |
1989年 | 22篇 |
1988年 | 21篇 |
1987年 | 21篇 |
1985年 | 16篇 |
1984年 | 25篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1979年 | 21篇 |
1977年 | 21篇 |
1975年 | 20篇 |
1974年 | 13篇 |
1973年 | 17篇 |
1972年 | 14篇 |
1971年 | 15篇 |
1970年 | 13篇 |
排序方式: 共有4048条查询结果,搜索用时 15 毫秒
121.
A. Thomas N. S. Borisov H. -J. Arends A. N. Fedorov G. M. Gurevich R. L. Kondratiev M. Korolija A. B. Lazarev M. Martinez W. Meyer S. V. Mironov A. B. Neganov V. N. Pavlov H. Ortega G. Reicherz Yu. A. Usov 《Physics of Particles and Nuclei》2013,44(6):964-967
The new frozen spin polarized target for experiments at the polarized beam of the real photon facility A2 of the MAMI accelerator is described. The A2-collaboration at the Mainz Microtron MAMI is measuring photon absorption cross section using circularly and linearly polarized photons up to the energy of 1.5 GeV. The photons are produced in the’ Bremsstrahlungs’ process. In the years 2005/2006 the Crystal Ball detector with its unique capability to cope with multi photon final states was set up in Mainz. Since 2010 the experimental apparatus has been completed by a polarized target. The horizontal dilution refrigerator of the Frozen-Spin Target has been constructed and is operated in close cooperation with the Joint Institute for Nuclear Research in Dubna, Russia. The system offers the opportunity to provide longitudinally and transversely polarized protons and deuteron. In this paper the operation experience of this new Frozen-Spin Target and first results from the runs in 2010 and 2011 are presented. 相似文献
122.
G. V. Fedorov 《Doklady Mathematics》2018,98(3):607-611
In this paper, we find new identities and asymptotic formulas in the problem of multiplicative partitions, which is an analogue of the multidimensional problem of Dirichlet divisors with the condition of disorder of the factors. 相似文献
123.
124.
N. N. Rozanov S. V. Fedorov R. S. Savel’ev A. A. Sukhorukov Yu. S. Kivshar 《Journal of Experimental and Theoretical Physics》2012,114(5):782-791
The frequency dependence of the gain required to compensate for absorption is determined for a layered structure consisting of alternating absorbing and amplifying layers. It is shown that the fulfillment of the same conditions is required for the existence of a band structure consisting of alternating bands allowed and forbidden for optical radiation propagation in the frequency-wave vector parametric region. Conditions are found under which the gain required for compensation is smaller than thresholds for absolute (parasitic lasing) and convective (waveguide amplification of radiation) instabilities. 相似文献
125.
Eletskii A. V. Sarychev A. K. Boginskaya I. A. Bocharov G. S. Gaiduchenko I. A. Egin M. S. Ivanov A. V. Kurochkin I. N. Ryzhikov I. A. Fedorov G. E. 《Doklady Physics》2018,63(12):496-498
Doklady Physics - The effect of Raman scattering (RLS) signal amplification by carbon nanotubes (CNTs) was studied. Single-layered nanotubes were synthesized by the chemical vapor deposition (CVD)... 相似文献
126.
127.
A. E. Sovestnov A. A. Naberezhnov Yu. A. Kumzerov A. A. Sysoeva V. A. Ganzha A. I. Egorov N. M. Okuneva V. I. Fedorov E. V. Fomin 《Physics of the Solid State》2013,55(4):837-841
Metallic Pd synthesized in porous glass with an average pore diameter of 7 ± 2 nm has been studied using the X-ray diffraction and X-ray line shift methods for the first time. The irregular dependence of the reflection width in X-ray patterns on the diffraction angle has been revealed. This can be caused by crystallite growth mostly in the [111] direction or by tetrahedral distortions of the fcc lattice. The shift (difference in energy) of K α1 lines (ΔE α1 = 19 ± 2 meV) for nanostructured Pd in comparison with the bulk material is first detected. The detected effect is considered within the assumption of the palladium electron redistribution between Pd 5s- and 4d-bands. 相似文献
128.
Mikhail N. Feofanov Boris A. Lozhkin Maksim V. Anokhin Alexey D. Averin Irina P. Beletskaya 《Mendeleev Communications》2018,28(4):429-430
Magnesium iodide-catalyzed addition of electron-rich (het)arenes to ethyl glyoxylate proceeds at room temperature with high chemoselectivity to afford ethyl 2-(het)aryl- 2-hydroxyacetates in yields up to 95%. 相似文献
129.
130.
Dmitry I. Bugaenko Alexey A. Volkov Dr. Mikhail V. Livantsov Prof. Dr. Marina A. Yurovskaya Dr. Alexander V. Karchava 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(54):12502-12506
The visible-light-induced arylation of tertiary phosphines with aryl(mesityl)iodonium triflates to produce the quaternary phosphonium salts occurs under mild, metal, and catalyst-free conditions. Photo-excited EDA complexes between diaryliodonium salts and phosphines supposedly enable this transformation, which is difficult to achieve through the traditional ground-state reactions. Demonstrating high functional group tolerance, broad scope, and complete selectivity of the aryl group transfer, the method is particularly compatible with sterically congested phosphines, which are challenging under metal-based catalytic methods. 相似文献