全文获取类型
收费全文 | 8195篇 |
免费 | 417篇 |
国内免费 | 62篇 |
专业分类
化学 | 5754篇 |
晶体学 | 81篇 |
力学 | 315篇 |
数学 | 1088篇 |
物理学 | 1436篇 |
出版年
2023年 | 56篇 |
2022年 | 193篇 |
2021年 | 272篇 |
2020年 | 224篇 |
2019年 | 308篇 |
2018年 | 277篇 |
2017年 | 204篇 |
2016年 | 377篇 |
2015年 | 266篇 |
2014年 | 405篇 |
2013年 | 828篇 |
2012年 | 507篇 |
2011年 | 530篇 |
2010年 | 391篇 |
2009年 | 344篇 |
2008年 | 393篇 |
2007年 | 341篇 |
2006年 | 319篇 |
2005年 | 246篇 |
2004年 | 251篇 |
2003年 | 211篇 |
2002年 | 237篇 |
2001年 | 99篇 |
2000年 | 144篇 |
1999年 | 93篇 |
1998年 | 63篇 |
1997年 | 62篇 |
1996年 | 64篇 |
1995年 | 52篇 |
1994年 | 58篇 |
1993年 | 58篇 |
1992年 | 55篇 |
1991年 | 46篇 |
1990年 | 32篇 |
1989年 | 49篇 |
1988年 | 53篇 |
1987年 | 33篇 |
1986年 | 26篇 |
1985年 | 55篇 |
1984年 | 38篇 |
1983年 | 31篇 |
1982年 | 39篇 |
1981年 | 44篇 |
1980年 | 33篇 |
1979年 | 26篇 |
1978年 | 26篇 |
1976年 | 22篇 |
1975年 | 25篇 |
1974年 | 21篇 |
1973年 | 19篇 |
排序方式: 共有8674条查询结果,搜索用时 15 毫秒
991.
Theoretical and Mathematical Physics - We present a supersymmetric generalization of a multicomponent coupled dispersionless (SUSY-MCD) integrable system. Expanding the superfields of the SUSY-MCD... 相似文献
992.
Periodica Mathematica Hungarica - We discuss the rational solutions of the Diophantine equations $$f(x)^2 \pm f(y)^2=z^2$$ . This problem can be solved either by the theory of elliptic curves or by... 相似文献
993.
Hicham Benaissa El‐Hassan Benkhira Rachid Fakhar Abdelhadi Hachlaf 《Mathematical Methods in the Applied Sciences》2019,42(4):1292-1311
We consider here a mathematical model describing the bilateral frictional contact between a thermo‐piezoelectric body and a thermally conductive foundation. We model the behavior of the material with a linear thermo‐electro‐elastic constitutive law. The process is assumed to be quasistatic and the contact is modeled with a nonlocal version of Coulomb's dry friction law, in which the frictional heat generated in the process, is taken into account. We drive a variational formulation of the problem and establish the existence of its weak solution. 相似文献
994.
Mohammed K. Almoaeet Mostafa Shamsi Hassan Khosravian‐Arab Delfim F. M. Torres 《Mathematical Methods in the Applied Sciences》2019,42(10):3465-3480
We present the method of lines (MOL), which is based on the spectral collocation method, to solve space‐fractional advection‐diffusion equations (SFADEs) on a finite domain with variable coefficients. We focus on the cases in which the SFADEs consist of both left‐ and right‐sided fractional derivatives. To do so, we begin by introducing a new set of basis functions with some interesting features. The MOL, together with the spectral collocation method based on the new basis functions, are successfully applied to the SFADEs. Finally, four numerical examples, including benchmark problems and a problem with discontinuous advection and diffusion coefficients, are provided to illustrate the efficiency and exponentially accuracy of the proposed method. 相似文献
995.
In this paper, we study pseudo-slant submanifolds and their warped products in Kenmotsu manifolds. We obtain the necessary conditions that a pseudoslant submanifold is locally a warped product and establish an inequality for the squared norm of the second fundamental form in terms of the warping function. The equality case is also considered. 相似文献
996.
Czechoslovak Mathematical Journal - Let K be a number field defined by an irreducible polynomial F(X) ∈ ?[X] and ?K its ring of integers. For every prime integer p, we give... 相似文献
997.
Aadil Lahrouz Adel Settati Mohamed El Fatini Abdessamad Tridane 《Mathematical Methods in the Applied Sciences》2021,44(1):1137-1146
In this paper, we aim to analyze the classical SIS epidemic model with a generalized force of infection (including nonmonotonic cases), where the transmission rate is perturbed by white noise. Using Feller's test for explosions, we prove that the disease dies out with probability one without any restriction on the model parameters. 相似文献
998.
On the basis of a well-established binomial structure and the so-called Poisson-Lindley distribution,a new two-parameter discrete distribution is introduced.Its... 相似文献
999.
Faisal A. Almalki Ashraf N. Abdalla Ahmed M. Shawky Mahmoud A. El Hassab Ahmed M. Gouda 《Molecules (Basel, Switzerland)》2021,26(13)
In the current study, a simple in silico approach using free software was used with the experimental studies to optimize the antiproliferative activity and predict the potential mechanism of action of pyrrolizine-based Schiff bases. A compound library of 288 Schiff bases was designed based on compound 10, and a pharmacophore search was performed. Structural analysis of the top scoring hits and a docking study were used to select the best derivatives for the synthesis. Chemical synthesis and structural elucidation of compounds 16a–h were discussed. The antiproliferative activity of 16a–h was evaluated against three cancer (MCF7, A2780 and HT29, IC50 = 0.01–40.50 μM) and one normal MRC5 (IC50 = 1.27–24.06 μM) cell lines using the MTT assay. The results revealed the highest antiproliferative activity against MCF7 cells for 16g (IC50 = 0.01 μM) with an exceptionally high selectivity index of (SI = 578). Cell cycle analysis of MCF7 cells treated with compound 16g revealed a cell cycle arrest at the G2/M phase. In addition, compound 16g induced a dose-dependent increase in apoptotic events in MCF7 cells compared to the control. In silico target prediction of compound 16g showed six potential targets that could mediate these activities. Molecular docking analysis of compound 16g revealed high binding affinities toward COX-2, MAP P38α, EGFR, and CDK2. The results of the MD simulation revealed low RMSD values and high negative binding free energies for the two complexes formed between compound 16g with EGFR, and CDK2, while COX-2 was in the third order. These results highlighted a great potentiality for 16g to inhibit both CDK2 and EGFR. Taken together, the results mentioned above highlighted compound 16g as a potential anticancer agent. 相似文献
1000.
A. M. El Mahdy 《Molecular physics》2013,111(22):3531-3544
Hydrogen storage reactions on Pd-doped C60 fullerene are investigated by using the state-of-the-art density functional theory calculations. The Pd atom prefers to bind at the bridge site between two hexagonal rings, and can bind up to four hydrogen molecules with average adsorption energies of 0.61, 0.45, 0.32, and 0.21 eV per hydrogen molecule. With no metal clustering, the system gravimetric capacities are expected to be as large as 5.8 wt%. While the desorption activation barriers of the complexes nH2 + Pd–C60 with n = 1 are outside the department of energy (DOE) domain (?0.2 to ?0.6 eV), the desorption activation barriers of the complexes nH2 + Pd–C60 with n = 2–4 are inside this domain. While the interaction of 1H2 with Pd + C60 is irreversible at 459 K, the interaction of 2H2 with Pd + C60 is reversible at 529 K. The hydrogen storage of the irreversible 1H2 + Pd–C60 and reversible 2H2 + Pd–C60 interactions are characterised in terms of densities of states, infrared, Raman, and proton magnetic resonance spectra, electrophilicity, and statistical thermodynamic stability. 相似文献