全文获取类型
收费全文 | 3539篇 |
免费 | 134篇 |
国内免费 | 19篇 |
专业分类
化学 | 2283篇 |
晶体学 | 33篇 |
力学 | 42篇 |
数学 | 549篇 |
物理学 | 785篇 |
出版年
2023年 | 21篇 |
2022年 | 33篇 |
2021年 | 57篇 |
2020年 | 69篇 |
2019年 | 84篇 |
2018年 | 64篇 |
2017年 | 62篇 |
2016年 | 153篇 |
2015年 | 122篇 |
2014年 | 153篇 |
2013年 | 289篇 |
2012年 | 200篇 |
2011年 | 231篇 |
2010年 | 152篇 |
2009年 | 139篇 |
2008年 | 192篇 |
2007年 | 163篇 |
2006年 | 168篇 |
2005年 | 100篇 |
2004年 | 103篇 |
2003年 | 74篇 |
2002年 | 89篇 |
2001年 | 48篇 |
2000年 | 41篇 |
1999年 | 39篇 |
1998年 | 49篇 |
1997年 | 36篇 |
1996年 | 40篇 |
1995年 | 34篇 |
1994年 | 23篇 |
1993年 | 35篇 |
1992年 | 37篇 |
1991年 | 28篇 |
1990年 | 24篇 |
1989年 | 20篇 |
1988年 | 19篇 |
1987年 | 30篇 |
1986年 | 22篇 |
1985年 | 26篇 |
1984年 | 24篇 |
1982年 | 18篇 |
1981年 | 24篇 |
1980年 | 24篇 |
1979年 | 21篇 |
1978年 | 21篇 |
1977年 | 18篇 |
1976年 | 21篇 |
1975年 | 27篇 |
1974年 | 23篇 |
1969年 | 22篇 |
排序方式: 共有3692条查询结果,搜索用时 0 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.
V. Čápek 《Czechoslovak Journal of Physics》1991,41(10):975-989
A review of ideas leading to full rejection of any finite or partially-infinite order kinetic equation linearized in external field is given on grounds of the time-convolution Generalized Master Equations (GME). By two examples (two-level and band conduction problem), it is shown how standard kinetic equations result from GME in the lowest order approximations which obscure, however, a direct correspondence with the Kubo linear response theory. Without approximations, on the other hand, the rigorous approach is shown to be fully equivalent with the Kubo results. It is argued and illustrated that usual technical simplicity and seeming physical lucidity of standard theories (connected with the presence of field-independent transfer or scattering rates in the fielddependent linearized theory) are just owing to structural features which are solely due to the lowest order approximations involved. These features (i.e. also the possibility of standard physical interpretation of kinetic phenomena) are proved to disappear completely as far as the theory goes properly to higher orders. 相似文献
6.
I. M. Kolthoff S. R. Cooper V. J. Tulane F. Reimers H. A. J. Pieters K. Höppner V. H. Matula C. B. Macek W. N. Skworzow J. S. Schepelewa F. Čuta K. Kámen S. Cohen R. E. Oesper D. S. Narayanamurthi T. R. Seshadri H. M. State A. W. Kirssanow W. M. Tscherkassow D. M. Mukherjee T. Akiyama Y. Mine S. Yabe Y. Volmar M. Déribéré 《Analytical and bioanalytical chemistry》1937,111(5-6):192-197
7.
We predict ultraslow collapse of “tubular image states” (TIS) on material surfaces. TIS are bound Rydberg-like electronic states formed at large distances (∼30 nm) from the surfaces of suspended circularly-symmetric nanowires, such as metallic C nanotubes. The states are formed in potential wells, resulting from a combination of the TIS-electron attraction to image charges in the nanotube and its centrifugal repulsion, caused by spinning around the tube. We demonstrate that TIS can collapse on the tube surface by passing their angular momentum l to circularly polarized flexural phonons excited in the tube. Our analysis shows that for highly detached TIS with l ? 6 the relaxation lifetimes are of the order of 10 ns-1 μs, while for l < 6 these lifetimes are reduced by several orders of magnitude. 相似文献
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.
JOSEF MÁLEK JINDŘICH NEČAS K. R. RAJAGOPAL 《Archive for Rational Mechanics and Analysis》2002,165(3):243-269
To describe the flows of fluids over a wide range of pressures, it is necessary to take into account the fact that the viscosity
of the fluid depends on the pressure. That the viscosity depends on the pressure has been verified by numerous careful experiments.
While the existence of solutions local-in-time to the equations governing the flows of such fluids are available for small,
special data and rather unrealistic dependence of the viscosity on the pressure, no global existence results are in place.
Our interest here is to establish the existence of weak solutions for spatially periodic three-dimensional flows that are
global in time, for a large class of physically meaningful viscosity-pressure relationships.
(Accepted May 1, 2002) Published online November 15, 2002
Communicated by S. S. ANTMAN 相似文献
10.
Pavla Fialová Inmaculada Robina Petr Sedmera Lucie Petrásková-Hušáková 《Tetrahedron letters》2005,46(50):8715-8718
Glycosyl azides are new efficient donors for glycosidases. Their high water solubility facilitates transglycosylations with comparable or better yields than common O-glycosides. The azido group totally changes the β-GalNAc-ase/β-GlcNAc-ase ratio in β-N-acetylhexosaminidases (from the usual 0.3-1.0 to <0.01), contrary to all known aglycons. 相似文献