全文获取类型
收费全文 | 582篇 |
免费 | 1篇 |
专业分类
化学 | 268篇 |
晶体学 | 6篇 |
力学 | 23篇 |
数学 | 56篇 |
物理学 | 230篇 |
出版年
2022年 | 5篇 |
2021年 | 11篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 18篇 |
2017年 | 24篇 |
2016年 | 24篇 |
2015年 | 12篇 |
2014年 | 19篇 |
2013年 | 28篇 |
2012年 | 16篇 |
2011年 | 22篇 |
2010年 | 20篇 |
2009年 | 23篇 |
2008年 | 18篇 |
2007年 | 17篇 |
2006年 | 20篇 |
2005年 | 23篇 |
2004年 | 20篇 |
2003年 | 14篇 |
2002年 | 16篇 |
2001年 | 6篇 |
2000年 | 15篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 14篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 12篇 |
1990年 | 7篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1984年 | 3篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 10篇 |
1975年 | 8篇 |
1974年 | 7篇 |
1973年 | 5篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1969年 | 4篇 |
1967年 | 2篇 |
排序方式: 共有583条查询结果,搜索用时 15 毫秒
81.
Curvature,diameter and betti numbers 总被引:12,自引:0,他引:12
Michael Gromov 《Commentarii Mathematici Helvetici》1981,56(1):179-195
We give an upper bound for the Betti numbers of a compact Riemannian manifold in terms of its diameter and the lower bound
of the sectional curvatures. This estimate in particular shows that most manifolds admit no metrics of non-negative sectional
curvature. 相似文献
82.
V. T. Sirinjan S. S. Mnacakanov V. V. Gromov T. I. Perlova S. S. Ivancev 《Colloid and polymer science》1977,255(10):1039-1040
Ohne Zusammenfassung 相似文献
83.
E. M. Gromov L. V. Piskunova V. V. Tyutin 《Radiophysics and Quantum Electronics》1998,41(12):1051-1055
We present the results of numerical study of the evolution of wave packets and envelope soliton interaction in terms of the third-order nonlinear Schrödinger equation. It is shown that an arbitrary initial pulse evolves to a few solitons and a linear quasiperiodic wave. The interaction of solitons is accompanied by the radiation of part of the wave field in the form of a linear quasiperiodic wave from the interaction region, amplification of the soliton with larger amplitude and attenuation of the soliton with smaller amplitude. 相似文献
84.
85.
D.?R.?Zinatulina Ch.?Brian?on V.?B.?Brudanin R.?V.?Vasilyev K.?Ya.?Gromov V.?G.?Egorov C.?Petitjean V.?I.?Fominykh V.?G.?Chumin M.?V.?Shirchenko I.?A.?Yutlandov 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(6):825-828
The energy and time spectra of γ rays emitted during negative-muon capture in 150Sm were studied. The total muon lifetime in 150Sm was measured. The yields of several radioactive isotopes in this reaction were determined. The partial γ-ray yield upon muon capture by a 150Sm nucleus were measured. 相似文献
86.
S. A. Gavrilov D. G. Gromov A. M. Koz’min M. Yu. Nazarkin S. P. Timoshenkov A. S. Shulyat’ev E. S. Kochurina 《Physics of the Solid State》2013,55(7):1476-1479
A piezoelectric low-power nanogenerator based on an array of ZnO whisker nanocrystals and a movable flat top electrode has been developed. It has been shown that this element generates ac current under the effect of mechanical vibrations with a frequency up to 100 Hz, which makes it possible to accumulate the capacitor charge. The investigation of the sample on a vibration stand under the acceleration of 9.8 m/s2 has demonstrated that the stable variable signal from 50 mV to 1.5 V appears at a frequency of 20–120 Hz. The experimental dependence of the generated voltage on the weight of the load applied to the top electrode is obtained. The appearance of the ac signal is explained in the context of the classical piezoelectric effect, namely, the ZnO whisker nanocrystals in the starting state are already bent, and the different-sign charges are generated under the effect of mechanical vibrations during bending and unbending. 相似文献
87.
Dmitry Gromov Alexey Sherchenkov Egor Lebedev Alexey Babich Svetlana Nemtseva Yury Shaman Tomasz Maniecki Waldemar Maniukiewicz Pawel Mierczynski Radoslaw Ciesielski Sergey Gavrilov 《Journal of Thermal Analysis and Calorimetry》2018,134(1):35-44
The paper deals with the effect of the compression conditions on the propagation front velocity of exothermal reaction and the specific heat release in Al–Ni powder reactive materials with mean particle sizes of 70–110 nm. It was shown that the velocity increases from 2.7 to 8 cm s?1 and comes to saturation with the lowering of the porosity (η) from 0.91 to 0.34, while the dependence of the specific heat release has its maximum for η?=?0.5. The results of the X-ray diffraction analysis obtained in situ during the sample heating suggest that the sequence of phase transformations in the system does not depend on the porosity. In all cases, first in the temperature range of ~?500–540 °C the NiAl compound is formed. With the further heating up to ~?640 °C, the Ni3Al, Ni2Al3 and NiAl3 compounds are additionally formed. The calculation of kinetic parameters was performed using the obtained curves of the differential scanning calorimetry: activation energy, pre-exponential factor and reaction model. The comparison of the calculated results and the scanning electron microscopy data has shown that such behavior of the Al–Ni system with the porosity lowering occurs due to the growth of the transformation degree and is associated with the presence in the final powder mixture of mutually non-contacting Al and Ni agglomerates with the dimensions of over 10 μm. 相似文献
88.
89.
V. L. Ivanov R. R. Akhmetshin A. N. Amirkhanov A. V. Anisenkov V. M. Aulchenko V. S. Banzarov N. S. Bashtovoy D. E. Berkaev A. V. Bragin S. I. Eidelman D. A. Epifanov L. B. Epshteyn A. L. Erofeev G. V. Fedotovich S. E. Gayazov A. A. Grebenuk D. N. Grigoriev E. M. Gromov F. V. Ignatov S. V. Karpov V. F. Kazanin B. I. Khazin I. A. Koop O. A. Kovalenko A. N. Kozyrev E. A. Kozyrev P. P. Krokovny A. E. Kuzmenko A. S. Kuzmin I. B. Logashenko P. A. Lukin K. Yu. Mikhailov V. S. Okhapkin Yu. N. Pestov E. A. Perevedentsev A. S. Popov G. P. Razuvaev Yu. A. Rogovsky A. L. Romanov A. A. Ruban N. M. Ryskulov A. E. Ryzhenenkov V. E. Shebalin D. N. Shemyakin B. A. Shwartz D. B. Shwartz A. L. Sibidanov Yu. M. Shatunov P. Yu. Shatunov E. P. Solodov V. M. Titov A. A. Talyshev A. I. Vorobiov Yu. V. Yudin 《Physics of Atomic Nuclei》2016,79(2):251-259
We report preliminary results on the cross section of the process e+e? → φ(1020)η measured at 30 center-of-mass energy points in the range from 1.59 up to 2.0 GeV. Data analysis is based on the integrated luminosity of 22 pb?1 collected with the CMD-3 detector in 2011–2012. The obtained cross section agrees with the BaBar measurement and has better statistical accuracy. 相似文献
90.
SergeyP. Gromov ArtemI. Vedernikov EvgenyN. Ushakov LyudmilaG. Kuz'mina AlexeiV. Feofanov VitalyG. Avakyan AndreiV. Churakov YuriiS. Alaverdyan EkaterinaV. Malysheva MichaelV. Alfimov JudithA.K. Howard Bertil Eliasson UlfG. Edlund 《Helvetica chimica acta》2002,85(1):60-81
Butadienyl dyes of the benzothiazole series with various fragments of benzocrown ethers 1a – c were synthesized for the first time. The structures and spectral properties of crown‐containing butadienyl dyes and their complexes with alkali and alkaline‐earth metal cations were studied by X‐ray diffraction analysis and 1H‐NMR, UV/VIS, and resonance Raman spectroscopy. To interpret the experimental results, quantum‐chemical calculations were performed. In the case of Sr2+ and Ba2+ ions, the formation of strong sandwich complexes [M( 1b )2]2+ of an unusual structure involving stacking interactions was established; the dye molecules are arranged one above another in the complex according to the ‘head‐to‐head' pattern. 相似文献