全文获取类型
收费全文 | 160385篇 |
免费 | 34028篇 |
国内免费 | 24066篇 |
专业分类
化学 | 104659篇 |
晶体学 | 1741篇 |
力学 | 11043篇 |
综合类 | 783篇 |
数学 | 20547篇 |
物理学 | 79706篇 |
出版年
2023年 | 2370篇 |
2022年 | 2305篇 |
2021年 | 3086篇 |
2020年 | 4045篇 |
2019年 | 4382篇 |
2018年 | 4005篇 |
2017年 | 4254篇 |
2016年 | 5754篇 |
2015年 | 5984篇 |
2014年 | 6590篇 |
2013年 | 9946篇 |
2012年 | 11567篇 |
2011年 | 13357篇 |
2010年 | 14085篇 |
2009年 | 14133篇 |
2008年 | 8423篇 |
2007年 | 7614篇 |
2006年 | 6993篇 |
2005年 | 6650篇 |
2004年 | 6604篇 |
2003年 | 5206篇 |
2002年 | 4687篇 |
2001年 | 4798篇 |
2000年 | 3847篇 |
1999年 | 4310篇 |
1998年 | 3697篇 |
1997年 | 3387篇 |
1996年 | 3810篇 |
1995年 | 4029篇 |
1994年 | 4040篇 |
1993年 | 3850篇 |
1992年 | 3353篇 |
1991年 | 2920篇 |
1990年 | 2430篇 |
1989年 | 2423篇 |
1988年 | 2266篇 |
1987年 | 1549篇 |
1986年 | 1530篇 |
1985年 | 1231篇 |
1984年 | 1229篇 |
1983年 | 568篇 |
1982年 | 1053篇 |
1981年 | 869篇 |
1980年 | 862篇 |
1979年 | 588篇 |
1978年 | 603篇 |
1977年 | 708篇 |
1976年 | 1111篇 |
1973年 | 504篇 |
1972年 | 573篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
Circularly polarized luminescence (CPL) has attracted attention as a next-generation light signal because of its carrying more information compared with normal and linearly polarized lights as well as its potential wide application in information fields. Recently, much attention has been paid to small organic molecules-based CPL emitters because of easy synthesis, fine structural modification at molecular level, and tunable wide range emission wavelength. This review highlights the development of small organic molecules-based CPL emitters in the past 5 years (2017–2021). The progress suggests that small organic molecules-based CPL emitters provide a simple and efficient way to generate CPL. 相似文献
2.
The surface charge is a key concept in electrochemistry. Mathematically, the surface charge is obtained from a spatial integration of the volume charge along a particular direction. Ambiguities thus arise in choosing the starting and ending points of the integration. As for electrocatalytic interfaces, the presence of chemisorbates further complicates the situation. In this minireview, I adopt a definition of the surface charge within a continuum picture of the electric double layer. I will introduce surface charging behaviors of firstly ordinary electrochemical interfaces and then electrocatalytic interfaces featuring partially charged chemisorbates. Particularly, the origin of nonmonotonic surface charging behaviors of electrocatalytic interfaces is explained using a primitive model. Finally, a brief account of previous studies on the nonmonotonic surface charging behavior is presented, as a subline of the spectacular history of electric double layer. 相似文献
3.
In this paper,we consider the deformed Hermitian-Yang-Mills equation on closed almost Hermitian manifolds.In the case of the hypercritical phase,we derive a priori estimates under the existence of an admissible C-subsolution.As an application,we prove the existence of solutions for the deformed Hermitian-Yang-Mills equation under the condition of existence of a supersolution. 相似文献
4.
Nonlinear Dynamics - The perovskite solar cell (PSC) is one of the most promising photovoltaic candidates along with the highly increasing demand for green electricity. One of the main concerns... 相似文献
5.
Science China Chemistry - Human health is always under global spotlight, but now it suffers from severe environmental issue and various diseases. Developing highly selective and effective... 相似文献
6.
Xin Liu Lili Chen Yanfeng Zhao Xianhua Song 《Mathematical Methods in the Applied Sciences》2022,45(1):77-92
In this paper, the problem of the uniform stability for a class of fuzzy fractional-order genetic regulatory networks with random discrete delays, distributed delays, and parameter uncertainties is studied. Although there is a portion of literature on using fixed point theorems to study the stability of fractional neural networks, most of them required the fractional order to be in . However, the case of the fractional-order belonging to has not been discussed. To solve it, this work proposes a novel idea of using fixed point theory to study the stability of fuzzy (0,1) order neural networks, the problem of the uniqueness of the solution of the considered genetic regulatory networks is resolved, and a novel sufficient condition to guarantee the uniform stability of above genetic regulatory networks is also derived. Eventually, an example is given to demonstrate that the obtained result is effective. 相似文献
7.
8.
以全血样品为原料,探讨湿法消解-原子荧光法测定全血中的硒含量。血样经硝酸-高氯酸消解后,用硼氢化钠将硒还原成硒化氢,由氩气载入原子化器,产生的原子荧光强度与试液中硒元素含量在一定范围内呈正比,外标法定量。以消解效率为指标,优化样品的消解条件,测定血中硒在0-10μg/L范围内线性情况良好,相关系数为0.9992,最低检出限为0.143μg/L,相对标准偏差为1.51%-1.58%,平均加标回收率为90.86%-104.62%。血中硒的原子荧光测定法灵敏度高,精密度和稳定性好,可应用于血中硒的生物监测。 相似文献
9.
Majorana fermions induced fast-and slow-light in a hybrid semiconducting nanowire/superconductor device 下载免费PDF全文
We investigate theoretically Rabi-like splitting and Fano resonance in absorption spectra of quantum dots(QDs)based on a hybrid QD-semiconducting nanowire/superconductor(SNW/SC)device mediated by Majorana fermions(MFs).Under the condition of pump on-resonance and off-resonance,the absorption spectrum experiences the conversion from Fano resonance to Rabi-like splitting in different parametric regimes.In addition,the Fano resonances are accompanied by the rapid normal phase dispersion,which will indicate the coherent optical propagation.The results indicate that the group velocity index is tunable with controlling the interaction between the QD and MFs,which can reach the conversion between the fast-and slow-light.Fano resonance will be another method to detect MFs and our research may indicate prospective applications in quantum information processing based on the hybrid QD-SNW/SC devices. 相似文献
10.
Annals of Global Analysis and Geometry - In this paper, we prove a family of sharp geometric inequalities for free boundary hypersurfaces in a ball in space forms. 相似文献