全文获取类型
收费全文 | 352篇 |
免费 | 7篇 |
国内免费 | 3篇 |
专业分类
化学 | 258篇 |
晶体学 | 8篇 |
力学 | 24篇 |
数学 | 15篇 |
物理学 | 57篇 |
出版年
2023年 | 6篇 |
2022年 | 19篇 |
2021年 | 15篇 |
2020年 | 13篇 |
2019年 | 15篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 15篇 |
2013年 | 27篇 |
2012年 | 25篇 |
2011年 | 22篇 |
2010年 | 5篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 16篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 12篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有362条查询结果,搜索用时 15 毫秒
71.
Nonlinear Dynamics - In this paper we show how higher-order averaging can be used to remedy serious technical issues with the direct application of the averaging theorem. While doing so, we... 相似文献
72.
Aziz Taha Javaid Saba Aziz Asim Sadiq M. A. 《Journal of Thermal Analysis and Calorimetry》2021,143(2):985-1002
Journal of Thermal Analysis and Calorimetry - The fully developed boundary layer flow and heat transfer model of an unsteady, incompressible, electrically conducting, optically thick and... 相似文献
73.
Bruce B. Jarvis Yin-Won Lee F.Taha Cömezoḡlu S.Nilgün Cömezoḡlu George A. Bean 《Tetrahedron letters》1985,26(40):4859-4862
An isolate of which is a pathogen on tomatoes in Texas produces a new class of C27 macrocyclic trichothecenes which contains a nonconjugated diene system that includes a vinyl ether group. 相似文献
74.
The nonlinear Schrödinger equation is of tremendous interest in both theory and applications. Various regimes of pulse propagation in optical fibers are modeled by some form of the nonlinear Schrödinger equation. In this paper we introduce sequential and parallel split-step Fourier methods for numerical simulations of the nonlinear Schrödinger-type equations. The parallel methods are implemented on the Origin 2000 multiprocessor computer. Our numerical experiments have shown that these methods give accurate results and considerable speedup. 相似文献
75.
We consider electromagnetic waves propagating in a periodic medium characterized by two small scales. We perform the corresponding homogenization process, relying on the modelling by Maxwell partial differential equations. 相似文献
76.
Magdy E. Amin N. H. Abdel-Wahab M. Taha 《International Journal of Theoretical Physics》2004,43(2):411-420
We study the interaction between a one-mode electromagnetic field and a two-level atom in the presence of a Kerr-like medium when the atom is prepared initially in the momentum eigenstate. The wave function is calculated by using the Schrodinger equation for a coherent electromagnetic field and an atom in the excited state. The effects of the Kerr-like medium and the detuning parameters on the statistical aspects of the intensity-dependent-coupling Hamiltonian such as, atomic momentum increment, momentum diffusion, the radiation force, and the field entropy are calculated. We investigate the effect of the detuning, Kerr-like medium and photon number operator on the field entropy. 相似文献
77.
Polyethylene macromolecular free radical initiators, obtained by ozonization, are used to prepare graft copolymers with methyl methacrylate, styrene and vinyl chloride. The reactions parameters are the number of initiator groups (found by DPPH), peroxide and hydroperoxide proportions (respectively 36 and 64%), decomposition rate (Kd at 90° 10−1sec−1) and monomer concentration. The molecular structure of these copolymers is defined. 相似文献
78.
The dissociation constants of 3-phenylhydrazo-pentane-2, 4-dione and its o-, m-, p-carboxy derivatives, and the stability constants of complexes of divalent metal ions with the o-carboxy derivative are determined by pH-metric method. The ir-spectra of the ligands and some divalent metal complexes with the o-derivative are discussed. 相似文献
79.
Isolation,identification, and keratinolytic activity of several feather-degrading bacterial isolates
Several feather-degrading bacterial isolates were isolated from Egyptian soil. These isolates were able to degrade chicken
feather, when grown on basal medium containing 1% native feather as a source of energy, carbon, and nitrogen. Feather waste,
generated in large quantities as a byproduct of commercial poultry processing, is nearly pure keratin, which is not easily
degradable by common proteolytic enzymes. The isolates were identified according to the morphological characteristics, biochemical
tests, and API 50 CHBBacillus system. Proteolytic and keratinolytic activities of these isolates were monitored throughout the cultivation of the bacterial
isolates on feather. Resulting soluble proteins, which were released as a result of the biodegradation of feather, were demonstrated
by SDS-PAGE. 相似文献
80.
The study of the oxidation of low density polyethylene is carried out under fluidized conditions in air and ozone. Special attention is paid to the formation of peroxides and hydroperoxides. Their production is optimized according to various parameters (temperature, time, quantity of ozone, flow of the gaseous current) using an experimental design method. Peroxides and hydroperoxides are titrated by a colorimetric method using diphenylpicrylhydrazyl as reagent. A correlation between i.r. carbonyl ratio and the yield of peroxides has been established. 相似文献