全文获取类型
收费全文 | 4310篇 |
免费 | 379篇 |
国内免费 | 109篇 |
专业分类
化学 | 533篇 |
晶体学 | 24篇 |
力学 | 362篇 |
综合类 | 9篇 |
数学 | 1793篇 |
物理学 | 2077篇 |
出版年
2024年 | 7篇 |
2023年 | 77篇 |
2022年 | 132篇 |
2021年 | 184篇 |
2020年 | 204篇 |
2019年 | 135篇 |
2018年 | 145篇 |
2017年 | 207篇 |
2016年 | 263篇 |
2015年 | 237篇 |
2014年 | 311篇 |
2013年 | 290篇 |
2012年 | 380篇 |
2011年 | 273篇 |
2010年 | 257篇 |
2009年 | 283篇 |
2008年 | 146篇 |
2007年 | 162篇 |
2006年 | 209篇 |
2005年 | 132篇 |
2004年 | 59篇 |
2003年 | 71篇 |
2002年 | 84篇 |
2001年 | 174篇 |
2000年 | 57篇 |
1999年 | 208篇 |
1998年 | 96篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1986年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有4798条查询结果,搜索用时 218 毫秒
1.
Acta Mathematicae Applicatae Sinica, English Series - A subset I of vertices of an undirected connected graph G is a nonseparating independent set (NSIS) if no two vertices of I are adjacent and G... 相似文献
2.
Russian Physics Journal - Aiming at problems of low probability of interception and poor anti-jamming performance of the multi-output radar, the numerical simulation based on a chaos optimization... 相似文献
3.
4.
5.
Cobalt oxide (Co3O4) modified anatase titanium dioxide nanotubes (ATNTs) have been investigated for the electrochemical sensing of hydrogen peroxide (H2O2). ATNTs have been synthesized by a two-step anodization process. ATNTs were then modified with Co3O4 employing chemical bath deposition method. The structure and morphology of ATNTs and their modification with Co3O4 has been confirmed by X-ray diffraction by scanning electron microscopy. H2O2 sensing has been studied in 0.1 M PBS solution, by cyclic voltammetry and amperometry. Variation in the peak positions and current densities was observed with addition of H2O2 for Co3O4 modified ATNTs. Sensitivity and limit of detection improved with modification of ATNTs with Co3O4 with precursor concentration up to 0.8 M. However, at higher precursor concentrations sensitivity and limit of detection toward H2O2 deteriorated. Co3O4 Modified ATNTS using 0.8 M precursor concentration are comparatively more suitable for H2O2 sensing applications due to the optimum formation of Co3O4/ATNTs heterojunctions. 相似文献
6.
We discuss the notion of representing the values of physical quantities by the real numbers, and its limits to describe the nature to be understood in the relation to our appreciation that the quantum theory is a better theory of natural phenomena than its classical analog. Getting from the algebra of physical observables to their values for a fixed state is, at least for classical physics, really a homomorphic map from the algebra into the real number algebra. The limitation of the latter to represent the values of quantum observables with noncommutative algebraic relation is obvious. We introduce and discuss the idea of the noncommutative values of quantum observables and its feasibility, arguing that at least in terms of the representation of such a value as an infinite set of complex numbers, the idea makes reasonable sense theoretically as well as practically. 相似文献
7.
8.
9.
To construct a class of new multiwave interaction solutions for the (3+1)-dimensional generalized Kadomtsev-Petviashvili equation, we calculate different types of interaction solutions among solitons, periodic waves and rational waves using the direct algebraic method together with the inheritance solving skill. Moreover, a new algorithm is proposed with the aid of the simplified Hirota method, the conjugated parameters assignment and long wave limit strategies, from which multiwave interaction solutions among solitons, breathers and lump waves are generated. 相似文献
10.
The localized electrostatic structures with dissipation due to ion-neutral collisions in a symmetric warm pair-ion plasma in the presence of non-Maxwellian population of electrons are studied. The analytical model for ion dynamics is based on fluid equations and the evolution equation is derived by using the reductive perturbation scheme in the form of a damped Korteweg-de Vries equation. The parameter regime relevant to space-based observations and laboratory plasmas is considered and time evolution of the propagating ion-acoustic soliton is discussed. The energetic-particles-driven properties of soliton for various spectral indices, dissipation, ion temperature, and density are illustrated with comparison to the thermal mode for Boltzmann distribution of electrons. 相似文献