全文获取类型
收费全文 | 2538篇 |
免费 | 86篇 |
国内免费 | 19篇 |
专业分类
化学 | 1814篇 |
晶体学 | 23篇 |
力学 | 20篇 |
数学 | 367篇 |
物理学 | 419篇 |
出版年
2023年 | 17篇 |
2022年 | 39篇 |
2021年 | 60篇 |
2020年 | 61篇 |
2019年 | 68篇 |
2018年 | 53篇 |
2017年 | 54篇 |
2016年 | 108篇 |
2015年 | 85篇 |
2014年 | 109篇 |
2013年 | 176篇 |
2012年 | 177篇 |
2011年 | 223篇 |
2010年 | 128篇 |
2009年 | 114篇 |
2008年 | 167篇 |
2007年 | 145篇 |
2006年 | 138篇 |
2005年 | 98篇 |
2004年 | 95篇 |
2003年 | 63篇 |
2002年 | 64篇 |
2001年 | 28篇 |
2000年 | 22篇 |
1999年 | 21篇 |
1998年 | 26篇 |
1997年 | 18篇 |
1996年 | 25篇 |
1995年 | 16篇 |
1994年 | 9篇 |
1993年 | 20篇 |
1992年 | 12篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 17篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1977年 | 6篇 |
1975年 | 8篇 |
1973年 | 5篇 |
1970年 | 5篇 |
1966年 | 6篇 |
1958年 | 6篇 |
1955年 | 9篇 |
排序方式: 共有2643条查询结果,搜索用时 15 毫秒
31.
Veselov Mark S. Ivanenkov Yan A. Yamidanov Renat S. Osterman Ilya A. Sergiev Petr V. Aladinskiy Vladimir A. Aladinskaya Anastasia V. Terentiev Victor A. Ayginin Andrey A. Skvortsov Dmitry A. Komarova Katerina S. Chemeris Alexey V. Baimiev Alexey Kh. Sofronova Alina A. Machulkin Alexey E. Petrov Rostislav A. Maklakova Svetlana Yu. Bezrukov Dmitry S. Filkov Gleb I. Zainullina Liana F. Maximova Marina A. Zileeva Zulfiya R. Kartsev Victor G. Vakhitova Yulia V. Dontsova Olga A. 《Molecular diversity》2020,24(1):233-239
Molecular Diversity - A series of 5-oxo-4H-pyrrolo[3,2-b]pyridine derivatives was identified as novel class of highly potent antibacterial agents during an extensive large-scale high-throughput... 相似文献
32.
Petr Munster Tomas Horvath Josef Vojtech Ondrej Havlis Martin Slapak Pavel Skoda 《Fiber and Integrated Optics》2017,36(3):144-156
Currently, individual optical fibers are mostly used for each non-data application, which is very inefficient and uneconomical. Sharing a single fiber for multiple applications is a promising solution. However, in the case of a non-data application, the situation is much more complicated compared to data because of special application´s requirements. In laboratory setup, we performed a measurement with a standard G.652D optical fiber for analyzing possible interaction of stable frequency/accurate time transmission, 1.25/10Gbps data transmission (typical bitrates for access point-to-point networks), and high-power sensor signal for different channel spacing and different pulse duration of sensor signal. 相似文献
33.
S. S. Kovalenko K. A. Petržak K. Irmer G. Musiol 《Isotopes in environmental and health studies》2013,49(10):344-346
The TCAPM was developed to absolute and precise fission cross section measurement for neutron energies from 2 MeV up to 19 MeV. Experimental results of absolute fission cross section measurements on 233U, 235U, 238U, -237Np, 239Pu and 212Pu are given. Furthermore the TCAPM is suitable for the application of inelastic scattering of neutrons by the analysis of element contents. 相似文献
34.
Miroslav Jelínek Petr Písařík Tomáš Kocourek Josef Zemek Jaroslav Lukeš 《Applied Physics A: Materials Science & Processing》2013,110(4):943-947
A hybrid PLD system with ion bombardment of films was developed. Growing DLC films were modified during the laser deposition (10 J?cm?2) by argon ions with energy in the range from 40 eV to 210 eV and cathode current of 0.15 A and 0.5 A. The content of sp2 “graphitic” and sp3 “diamond” bonds was measured using XPS. Sp3 bonds changed from 60 % to 81 %. We found the highest sp3 content for energy of 40 eV. Hardness (and reduced Young’s modulus) were determined by nanoindentation and reached 49 GPa (277 GPa). Film adhesion was studied using the scratch test and was up to 14 N for titanium substrates. Relations among deposition conditions and measured properties are presented. 相似文献
35.
36.
Szymon Godlewski Jakub S. Prauzner-Bechcicki Janusz Budzioch Lukasz Walczak Irena G. Stará Ivo Starý Petr Sehnal Marek Szymonski 《Surface science》2012,606(21-22):1600-1607
Helicenes are carbon-rich materials with an ordered structure that possess interesting and remarkable electronic, chiroptical, mechanical and magnetic properties either in bulk or as single molecule devices. We report on the first attempt to anchor and organize [11]anthrahelicene ([11]AH) molecules onto a metal oxide surface. Molecular structures obtained on the (110) and (011) faces of rutile titania are characterized using scanning probe microscopy. On the (110) surface, [11]AH molecules form islands that are comprised of small domains of two types that are mirror reflections of each other and have an ordered quasi-hexagonal lattice. In contrast, molecules form unordered clusters on the (011) surface. Single molecules on both faces are imaged with sub-molecular resolution. 相似文献
37.
Highly sensitive room-temperature method of non-invasive in vivo detection of magnetic nanoparticles
Maxim P. Nikitin Petr M. Vetoshko Petr I. Nikitin 《Journal of magnetism and magnetic materials》2009,321(10):1658-1661
Methods of non-invasive in vivo quantification of magnetic nanoparticles (MP) have been proposed and realized. The methods are based on non-linear MP magnetization at two frequencies and measuring the response at combinatorial frequencies. The first method is developed for real-time study of MP dynamics and their clearance from the blood system of animals. High sensitivity of 3 ng of Fe3O4 in 0.1 ml was achieved for MP detection in mice tail veins. The second technique is proposed for MP detection inside animal tissues by an external probe. The proposed methods could essentially widen capabilities of biomedical research which involves magnetic nanoparticles. 相似文献
38.
A. Rod Gover Petr Somberg Vladimír Souček 《Communications in Mathematical Physics》2008,278(2):307-327
Working over a pseudo-Riemannian manifold, for each vector bundle with connection we construct a sequence of three differential
operators which is a complex (termed a Yang-Mills detour complex) if and only if the connection satisfies the full Yang-Mills
equations. A special case is a complex controlling the deformation theory of Yang-Mills connections. In the case of Riemannian
signature the complex is elliptic. If the connection respects a metric on the bundle then the complex is formally self-adjoint.
In dimension 4 the complex is conformally invariant and generalises, to the full Yang-Mills setting, the composition of (two
operator) Yang-Mills complexes for (anti-)self-dual Yang-Mills connections. Via a prolonged system and tractor connection
a diagram of differential operators is constructed which, when commutative, generates differential complexes of natural operators
from the Yang-Mills detour complex. In dimension 4 this construction is conformally invariant and is used to yield two new
sequences of conformal operators which are complexes if and only if the Bach tensor vanishes everywhere. In Riemannian signature
these complexes are elliptic. In one case the first operator is the twistor operator and in the other sequence it is the operator
for Einstein scales. The sequences are detour sequences associated to certain Bernstein-Gelfand-Gelfand sequences. 相似文献
39.
V. Petržílka 《Czechoslovak Journal of Physics》1997,47(2):183-196
Test particle motion and acceleration has been explored in strong radio frequency (RF) fields, for which quasilinear ponderomotive force approximation is not valid. By nonlinear acceleration in spatially varying wave amplitude of RF travelling wave, electrons may be accelerated to time averaged velocities significantly larger than the RF wave phase velocity, and than the boundary plasma thermal velocity, in RF fields of several Volts per centimeter at wave frequency of 7 MHz. It is also demonstrated that even weak spatial gradients, much weaker than those expected in experiments, of the RF wave field amplitude, have significant consequences for the particle motion. Estimates are presented of the total energy transferred from the near antenna RF field to the plasma due to the nonlinear electron acceleration effects. 相似文献
40.