全文获取类型
收费全文 | 7701篇 |
免费 | 169篇 |
国内免费 | 3篇 |
专业分类
化学 | 4124篇 |
晶体学 | 41篇 |
力学 | 190篇 |
数学 | 1771篇 |
物理学 | 1747篇 |
出版年
2021年 | 60篇 |
2020年 | 87篇 |
2019年 | 84篇 |
2018年 | 187篇 |
2017年 | 172篇 |
2016年 | 275篇 |
2015年 | 192篇 |
2014年 | 268篇 |
2013年 | 614篇 |
2012年 | 377篇 |
2011年 | 483篇 |
2010年 | 264篇 |
2009年 | 234篇 |
2008年 | 387篇 |
2007年 | 384篇 |
2006年 | 355篇 |
2005年 | 247篇 |
2004年 | 219篇 |
2003年 | 164篇 |
2002年 | 176篇 |
2001年 | 119篇 |
2000年 | 103篇 |
1999年 | 79篇 |
1998年 | 72篇 |
1997年 | 68篇 |
1996年 | 72篇 |
1995年 | 58篇 |
1994年 | 49篇 |
1993年 | 56篇 |
1992年 | 71篇 |
1991年 | 58篇 |
1990年 | 63篇 |
1989年 | 66篇 |
1988年 | 67篇 |
1987年 | 63篇 |
1986年 | 58篇 |
1985年 | 82篇 |
1984年 | 79篇 |
1983年 | 83篇 |
1982年 | 77篇 |
1981年 | 57篇 |
1980年 | 77篇 |
1979年 | 67篇 |
1978年 | 96篇 |
1977年 | 71篇 |
1976年 | 82篇 |
1975年 | 67篇 |
1974年 | 72篇 |
1973年 | 54篇 |
1972年 | 45篇 |
排序方式: 共有7873条查询结果,搜索用时 15 毫秒
1.
Tomáš Hložek Martin Štícha Miroslava Bursová Ivan Jelínek Petr Tůma Radomír Čabala 《Electrophoresis》2020,41(18-19):1564-1567
Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10–1000 ng/mL), with adequate accuracy (90.1–114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR. 相似文献
2.
3.
4.
5.
N. S. Simonović 《Few-Body Systems》2006,38(2-4):139-145
In agreement with the Kohn theorem the relative motion (rel) of three electrons in a two-dimensional parabolic trap separates
from the centre-of-mass (CM) motion. By introducing new coordinates the Hamiltonian for relative motion in the approximation
of non-interacting electrons can be taken to the normal form. The eigenstates of the normalized Hamiltonian are products of
the Fock-Darwin states for normal modes. The energy levels for relative motion are obtained by diagonalizing the exact Hamiltonian
in the eigenbasis for the non-interacting case. In this basis the interaction matrix elements can be obtained in the analytical
form. Since the rank of the Hamiltonian matrix is significantly reduced, the calculations are faster and more accurate than
those for the full (CM + rel) motion. This advantage is especially important for the calculations of excited states and the
analysis of energy spectra. 相似文献
6.
An experimental method for determining the real-time depth of laser-drilled holes is presented. The proposed method involves
detecting the laser-induced optoacoustic waves generated during the interaction of the laser beam with the material. Our optodynamic
study involved measuring the propagation times of these waves as they traveled through the material and analyzing their temporal
behavior during the drilling process. The experimental observations revealed an exponential relationship between the propagation
time of the longitudinal stress wave and the number of consecutive laser pulses.
Received: 25 October 2001 / Accepted: 27 October 2001 / Published online: 20 December 2001 相似文献
7.
8.
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
9.
We study condensation of ethanol-hexanol vapour by numerical solution of kinetic equations. The number of droplets formed
in unit volume is computed within self-consistent classical model. It is shown that formation of ethanol-rich droplets prevails
at the initial stage of nucleation process, but in the stationary state formation of droplets near the saddle point (on cluster
formation energy surface) plays the dominant role.
Presented at the 6th Joint Seminar “Development of Materials Science in Research and Education”, Karlštejn, Czech Republic,
17–19 September 1996.
This work was supported by Grant No. A1010615 of the Grant Agency of the Academy of Sciences of the Czech Republic. 相似文献
10.
The new techniques and ideas in quantum interferometry with neutrons, photons, atoms, electrons, and Bose condensates that fluorished in the last two decades have influenced in a decisive way the thinking and the research in the foundations and interpretation of quantum mechanics. The controversies existing among different schools on the reality of matter waves of quantum theory, the postulates of quantum measurement theory, and the (in)completeness of quantum mechanics have to be approached now in a new way. Our argumentation follows the spirit of the Paris school. 相似文献