全文获取类型
收费全文 | 3358篇 |
免费 | 21篇 |
国内免费 | 3篇 |
专业分类
化学 | 1307篇 |
晶体学 | 49篇 |
力学 | 99篇 |
数学 | 334篇 |
物理学 | 1593篇 |
出版年
2022年 | 38篇 |
2021年 | 71篇 |
2020年 | 69篇 |
2019年 | 69篇 |
2018年 | 113篇 |
2017年 | 91篇 |
2016年 | 121篇 |
2015年 | 50篇 |
2014年 | 86篇 |
2013年 | 150篇 |
2012年 | 116篇 |
2011年 | 121篇 |
2010年 | 134篇 |
2009年 | 105篇 |
2008年 | 152篇 |
2007年 | 154篇 |
2006年 | 125篇 |
2005年 | 127篇 |
2004年 | 101篇 |
2003年 | 102篇 |
2002年 | 84篇 |
2001年 | 96篇 |
2000年 | 76篇 |
1999年 | 45篇 |
1998年 | 39篇 |
1997年 | 46篇 |
1996年 | 41篇 |
1994年 | 25篇 |
1993年 | 38篇 |
1992年 | 37篇 |
1991年 | 42篇 |
1990年 | 35篇 |
1989年 | 37篇 |
1988年 | 32篇 |
1987年 | 28篇 |
1985年 | 32篇 |
1984年 | 31篇 |
1983年 | 27篇 |
1982年 | 26篇 |
1981年 | 28篇 |
1979年 | 34篇 |
1978年 | 33篇 |
1977年 | 43篇 |
1976年 | 34篇 |
1975年 | 28篇 |
1974年 | 29篇 |
1973年 | 34篇 |
1972年 | 29篇 |
1971年 | 28篇 |
1970年 | 22篇 |
排序方式: 共有3382条查询结果,搜索用时 16 毫秒
161.
Zaitseva Elvira R. Sokolov Anatolii I. Mikhaylov Andrey A. Baleeva Nadezhda S. Baranov Mikhail S. Smirnov Alexander Yu. 《Chemistry of Heterocyclic Compounds》2022,58(8-9):477-480
Chemistry of Heterocyclic Compounds - A methodology was developed for the synthesis of phenylspiro[imidazole-4,3'-thiochroman]ones by treatment of [2-(benzylsulfanyl)-benzylidene]imidazolones... 相似文献
162.
Bykov M. V. Abramov Z. D. Pakhomova M. V. Borodina T. N. Smirnov V. I. Suslov D. S. 《Journal of Structural Chemistry》2022,63(1):125-139
Journal of Structural Chemistry - The structure of complex [Pd(acac){P(NEt2)3}2]BF4 (I) is determined by XRD. In the crystal structure of I, the coordination sphere of palladium is characterized by... 相似文献
163.
Roman V. Tominov Zakhar E. Vakulov Vadim I. Avilov Daniil A. Khakhulin Nikita V. Polupanov Vladimir A. Smirnov Oleg A. Ageev 《Molecules (Basel, Switzerland)》2021,26(1)
We have experimentally studied the influence of pulsed laser deposition parameters on the morphological and electrophysical parameters of vanadium oxide films. It is shown that an increase in the number of laser pulses from 10,000 to 60,000 and an oxygen pressure from 3 × 10−4 Torr to 3 × 10−2 Torr makes it possible to form vanadium oxide films with a thickness from 22.3 ± 4.4 nm to 131.7 ± 14.4 nm, a surface roughness from 7.8 ± 1.1 nm to 37.1 ± 11.2 nm, electron concentration from (0.32 ± 0.07) × 1017 cm−3 to (42.64 ± 4.46) × 1017 cm−3, electron mobility from 0.25 ± 0.03 cm2/(V·s) to 7.12 ± 1.32 cm2/(V·s), and resistivity from 6.32 ± 2.21 Ω·cm to 723.74 ± 89.21 Ω·cm. The regimes at which vanadium oxide films with a thickness of 22.3 ± 4.4 nm, a roughness of 7.8 ± 1.1 nm, and a resistivity of 6.32 ± 2.21 Ω·cm are obtained for their potential use in the fabrication of ReRAM neuromorphic systems. It is shown that a 22.3 ± 4.4 nm thick vanadium oxide film has the bipolar effect of resistive switching. The resistance in the high state was (89.42 ± 32.37) × 106 Ω, the resistance in the low state was equal to (6.34 ± 2.34) × 103 Ω, and the ratio RHRS/RLRS was about 14,104. The results can be used in the manufacture of a new generation of micro- and nanoelectronics elements to create ReRAM of neuromorphic systems based on vanadium oxide thin films. 相似文献
164.
165.
Rozentsvet V. A. Sablina N. A. Ulyanova D. M. Smirnov S. N. Tolstoy P. M. 《Russian Chemical Bulletin》2021,70(4):773-779
Russian Chemical Bulletin - The structure of polymer chain of poly(1,3-pentadiene) synthesized via a stereospecific polymerization catalyzed by a system based on neodymium trichloride was... 相似文献
166.
V. V. Afrosimov A. A. Basalaev V. V. Kuz’michev M. N. Panov O. V. Smirnov 《Technical Physics》2016,61(3):342-348
The relative cross sections of elementary processes occurring in single collisions of tryptophan molecules in the gaseous phase with He2+ ions with energy 4 keV/u are measured using time-of-flight mass spectrometry for studying the mechanism of radiation damage of amino acid molecules. The fragmentation channels for intermediate singly and doubly charged tryptophan molecular ions formed during one-electron capture, two-electron capture, and electron capture with ionization are investigated. Significant difference is observed in the mass spectra of fragmentation of intermediate doubly charged ions formed during the capture with ionization and double capture, which is associated with different energies of excitation of {C11H12N2O2}2+* ions. 相似文献
167.
Shirai T Ikegami M Fujimoto S Souda H Tanabe M Tongu H Noda A Noda K Fujimoto T Iwata S Shibuya S Smirnov A Meshkov I Fadil H Grieser M 《Physical review letters》2007,98(20):204801
The ordering of protons has been observed at a new storage ring, S-LSR, at Kyoto University. Abrupt jumps in the momentum spread and the Schottky noise power were observed for protons for the first time at a particle number of approximately 2000, upon applying electron cooling with electron currents of 25, 50, and 100 mA. The transition temperature was 0.17 and 1 meV in the longitudinal and transverse directions, respectively. The transverse temperature of the proton beam was much below that of electrons at the transition, which played an essential role in the ordering of protons. 相似文献
168.
V. V. Shpeĭzman V. I. Nikolaev N. N. Peschanskaya A. E. Romanov B. I. Smirnov I. A. Aleksandrov N. A. Enikeev V. U. Kazykhanov A. A. Nazarov 《Physics of the Solid State》2007,49(4):678-683
The stress-strain compressive curves, temperature dependences of the yield stress, and small-inelastic-strain rate spectra of coarse-grained and ultrafine-grained (produced by equal-channel angular pressing) titanium and copper are compared in the temperature range 4.2–300 K. As the temperature decreases, copper undergoes mainly strain hardening and titanium undergoes thermal hardening. The temperature dependences of the yield stress of titanium and copper have specific features which correlate with the behavior of their small-inelastic-strain rate spectra. Under the same loading conditions, the rate of microplastic deformation of ultrafine-grained titanium is lower than that of coarse-grained titanium and the rate peaks shift toward high temperatures. The deformation activation volumes of titanium samples differing in terms of their grain size are (10–35)b 3, where b is the Burgers vector magnitude. The dependences of the yield stress on the grain size at various temperatures are satisfactorily described by the Hall-Petch relation. 相似文献
169.
I. Kh. Akopyan M. É. Labzovskaya B. V. Novikov V. M. Smirnov 《Physics of the Solid State》2007,49(7):1375-1381
The formation of the HgI2 crystalline phase in pores of various porous matrices and on their surfaces was studied. Based on the analysis of the evolution of the HgI2 optical spectra and electron and atomicforce microscopy data, it was shown that the formation of microcrystals of the stable red α modification is preceded by the formation and growth of particles of metastable yellow (β′) and orange modifications. The absorption edge of the β′ phase at T = 77 K is formed by excitonic transitions with an energy of ~2.7 eV. The Raman spectra of the β′ phase were compared to the spectra of known metastable yellow modifications. 相似文献
170.
R. Kh. Amirov N. A. Vorona A. V. Gavrikov G. D. Liziakin V. P. Polistchook I. S. Samoylov V. P. Smirnov R. A. Usmanov I. M. Yartsev 《Physics of Atomic Nuclei》2015,78(14):1631-1634
One of the key problems in the development of plasma separation technology is designing a plasma source which uses condensed spent nuclear fuel (SNF) or nuclear wastes as a raw material. This paper covers the experimental study of the evaporation and ionization of model materials (gadolinium, niobium oxide, and titanium oxide). For these purposes, a vacuum arc with a heated cathode on the studied material was initiated and its parameters in different regimes were studied. During the experiment, the cathode temperature, arc current, arc voltage, and plasma radiation spectra were measured, and also probe measurements were carried out. It was found that the increase in the cathode heating power leads to the decrease in the arc voltage (to 3 V). This fact makes it possible to reduce the electron energy and achieve singly ionized plasma with a high degree of ionization to fulfill one of the requirements for plasma separation of SNF. This finding is supported by the analysis of the plasma radiation spectrum and the results of the probe diagnostics. 相似文献