全文获取类型
收费全文 | 4591篇 |
免费 | 129篇 |
国内免费 | 25篇 |
专业分类
化学 | 2915篇 |
晶体学 | 47篇 |
力学 | 81篇 |
数学 | 896篇 |
物理学 | 806篇 |
出版年
2023年 | 42篇 |
2022年 | 65篇 |
2021年 | 134篇 |
2020年 | 104篇 |
2019年 | 123篇 |
2018年 | 137篇 |
2017年 | 113篇 |
2016年 | 154篇 |
2015年 | 127篇 |
2014年 | 128篇 |
2013年 | 291篇 |
2012年 | 247篇 |
2011年 | 313篇 |
2010年 | 203篇 |
2009年 | 207篇 |
2008年 | 249篇 |
2007年 | 239篇 |
2006年 | 226篇 |
2005年 | 226篇 |
2004年 | 188篇 |
2003年 | 146篇 |
2002年 | 121篇 |
2001年 | 77篇 |
2000年 | 58篇 |
1999年 | 41篇 |
1998年 | 39篇 |
1997年 | 38篇 |
1996年 | 35篇 |
1995年 | 26篇 |
1994年 | 30篇 |
1993年 | 36篇 |
1992年 | 21篇 |
1991年 | 34篇 |
1990年 | 21篇 |
1989年 | 19篇 |
1988年 | 22篇 |
1987年 | 17篇 |
1986年 | 23篇 |
1985年 | 23篇 |
1984年 | 36篇 |
1983年 | 20篇 |
1982年 | 22篇 |
1981年 | 28篇 |
1980年 | 24篇 |
1979年 | 25篇 |
1978年 | 37篇 |
1977年 | 27篇 |
1975年 | 23篇 |
1974年 | 18篇 |
1955年 | 15篇 |
排序方式: 共有4745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.
Avramenko Andriy A. Shevchuk Igor V. Dmitrenko Nataliia P. Skitsko Ivan F. 《Journal of Thermal Analysis and Calorimetry》2022,147(22):12709-12719
Journal of Thermal Analysis and Calorimetry - The paper focuses on the analytical analysis of the propagation of a normal shock wave in an adiabatic gas flow with nanoparticles. A modified... 相似文献
4.
5.
The copolymerization of methyl methacrylate and methacrylic acid in isopropyl alcohol is studied by kinetic, dynamic laser scattering and 13C-NMR methods. Correlations are established between the dependence of the copolymerization rate, the apparent average molecular weight, the diffusion coefficients and the configurational triad composition on the monomer feed. These correlations and the fact that both copolymerization constants are smaller than unity (rMMA = 0.63 ± 0.03; rMA = 0.25 ± 0.05) are in good agreement with the assumption that a comonomer complex takes part in the propagation reaction. A new Markov chain method for the estimation of the configurational triad mole fraction which accounts for the complex participation in a macromolecule formation is developed. Qualitative criteria for evidence the participation of the comonomer complex in copolymerization are proposed using experimental and terminal model calculated mole fractions of the compositional triads and diads. 相似文献
6.
Ivan Pan 《Comptes Rendus Mathematique》2005,341(7):439-443
We show that the first dynamical degree of a Cremona transformation stabilizing an irrational non elliptic curve is 1. Moreover, among these transformations, we characterize those which have finite order. To cite this article: I. Pan, C. R. Acad. Sci. Paris, Ser. I 341 (2005). 相似文献
7.
Cyclic Hypomonotonicity,Cyclic Submonotonicity,and Integration 总被引:9,自引:1,他引:8
Rockafellar has shown that the subdifferentials of convex functions are always cyclically monotone operators. Moreover, maximal cyclically monotone operators are necessarily operators of this type, since one can construct explicitly a convex function, which turns out to be unique up to a constant, whose subdifferential gives back the operator. This result is a cornerstone in convex analysis and relates tightly convexity and monotonicity. In this paper, we establish analogous robust results that relate weak convexity notions to corresponding notions of weak monotonicity, provided one deals with locally Lipschitz functions and locally bounded operators. In particular, the subdifferentials of locally Lipschitz functions that are directionally hypomonotone [respectively, directionally submonotone] enjoy also an additional cyclic strengthening of this notion and in fact are maximal under this new property. Moreover, every maximal cyclically hypomonotone [respectively, maximal cyclically submonotone] operator is always the Clarke subdifferential of some directionally weakly convex [respectively, directionally approximately convex] locally Lipschitz function, unique up to a constant, which in finite dimentions is a lower C2 function [respectively, a lower C1 function]. 相似文献
8.
9.
Impact of the internucleotide linkage modification by inserting a methylene group to the P-O bond (—O—PO
2
—
—O— chain changed for —O—PO
2
—
—CH2—O—), on the modified oligonucleotide binding ability to the natural DNA strand was studied by molecular dynamics simulation. Complex of (dT)11 with a deoxyadenosine undecamer containing alternating modified and natural internucleotide linkage was studied as a model system. The Amber force field was completed by a set of new parameters needed to model the modified part of the nucleotide. The simulations confirmed existence of a double-helical complex the melting point of which is considerably higher than 300 K. While the thymidine (unmodified) strand possesses a B-type secondary structure, the conformation of the adenosine (modified) strand is not stable at 300 K. The -ggt conformation of the modified linkages is highly preferred, temporary jumps to the -g-gt and ggt conformations were, however, observed. 相似文献
10.
Ivan Vitev 《Acta Physica Hungarica A》2006,27(2-3):281-286
We present an analytic model of jet quenching, based on the (D)GLV energy loss formalism, to describe the system size dependence of QGP-induced parton absorption in relativistic heavy ion collisions. Numerical simulations of the transverse momentum dependence of jet quenching are given for central Au+Au and Cu+Cu reactions. Low p Tdijet correlations are shown to be sensitive to the reappearance of the lost energy as soft hadrons. At high p Twe find that the attenuation of dihadrons is similar to that of single inclusive particles. Comparison to recent data from PHENIX and STAR is given as a test of the jet quenching theory. 相似文献