全文获取类型
收费全文 | 16886篇 |
免费 | 2952篇 |
国内免费 | 1993篇 |
专业分类
化学 | 12170篇 |
晶体学 | 192篇 |
力学 | 1206篇 |
综合类 | 89篇 |
数学 | 1805篇 |
物理学 | 6369篇 |
出版年
2024年 | 15篇 |
2023年 | 366篇 |
2022年 | 393篇 |
2021年 | 565篇 |
2020年 | 708篇 |
2019年 | 674篇 |
2018年 | 603篇 |
2017年 | 527篇 |
2016年 | 925篇 |
2015年 | 822篇 |
2014年 | 1005篇 |
2013年 | 1234篇 |
2012年 | 1625篇 |
2011年 | 1634篇 |
2010年 | 1082篇 |
2009年 | 1032篇 |
2008年 | 1165篇 |
2007年 | 1006篇 |
2006年 | 914篇 |
2005年 | 816篇 |
2004年 | 557篇 |
2003年 | 458篇 |
2002年 | 425篇 |
2001年 | 345篇 |
2000年 | 301篇 |
1999年 | 329篇 |
1998年 | 279篇 |
1997年 | 235篇 |
1996年 | 276篇 |
1995年 | 277篇 |
1994年 | 190篇 |
1993年 | 153篇 |
1992年 | 156篇 |
1991年 | 149篇 |
1990年 | 129篇 |
1989年 | 104篇 |
1988年 | 88篇 |
1987年 | 68篇 |
1986年 | 51篇 |
1985年 | 41篇 |
1984年 | 31篇 |
1983年 | 26篇 |
1982年 | 14篇 |
1981年 | 16篇 |
1980年 | 9篇 |
1978年 | 2篇 |
1959年 | 1篇 |
1957年 | 6篇 |
1937年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
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
2.
Hu Duo-Duo Gao Qian Dai Jing-Cheng Cui Ru Li Yuan-Bo Li Yuan-Ming Zhou Xiao-Guo Bian Kang-Jie Wu Bing-Bing Zhang Kai-Fan Wang Xi-Sheng Li Yan 《中国科学:化学(英文版)》2022,65(4):753-761
Science China Chemistry - A light-induced, nickel-catalyzed three-component arylsulfonation of 1,3-enynes in the absence of photocatalyst is reported. This methodology exhibited mild conditions,... 相似文献
3.
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
4.
Luo Dajuan Liu Bingqian Gao Rong Su Lixia Su Yonghuan 《Journal of Solid State Electrochemistry》2022,26(3):749-759
Journal of Solid State Electrochemistry - Cortisol, a steroid hormone, has been confirmed as a kind of biomarker that reflects the stress response of psychobiology and related adverse health... 相似文献
5.
本文基于新的Kronecker型替换,给出两个由黑盒表示的稀疏多项式的新确定性插值算法.令f∈R[x1,……,xn]是一个稀疏黑盒多项式,其次数上界为D.当R是C或者是有限域时,相对于已有算法,新算法具有更好的计算复杂度或者关于D的复杂度更低.特别地,对于一般黑盒模型,D是复杂度中的主要因素,而在所有的确定性算法中,本文的第二个算法的复杂度关于D是最低的. 相似文献
6.
Nonlinear Dynamics - Spiral waves in the cardiac tissue may cause life-threatening arrhythmia. Such waves can be anchored to a local heterogeneity and form stable pinned waves, which are difficult... 相似文献
7.
近年来,机器学习等人工智能技术被应用于蛋白质工程,其在蛋白质结构、功能预测、催化活性等研究中具有独特优势。在未知蛋白质结构的情况下,将蛋白质序列和功能特性与机器学习相结合,基于序列-活性关系(innovative sequence-activity relationship,ISAR)算法,将蛋白质氨基酸序列数字化,用快速傅里叶变换(fast four transform,FFT)进行预处理,再进行偏最小二乘回归建模,可在数据集较少情况下拟合得到最佳模型。通过机器学习对紫色球杆菌视紫红质(gloeobacter violaceus rhodopsin,GR)的突变体蛋白质氨基酸序列与光谱最大吸收波长进行建模,获得了最佳模型。用最佳索引LEVM760106建模得到的确定系数R2 为0.944,均方误差E为11.64。用小波变换进行的预处理,其R2 虽也约为0.944,但E大于11.64,不及FFT进行的预处理。方法较好地解决了蛋白质序列与功能特性之间的数学建模问题,在蛋白质工程中可为预测更优的突变体提供支持。 相似文献
8.
Heterostructured MoS2/GPC anode: the synergistic lithium storage performance and lithiation kinetics
Zhang Xia Dong Chaoyang Sun Yangang Liu Binyang Sun Lili Lu Yongjuan Yu Jing Wei Yajun Xu Yuandong 《Journal of Solid State Electrochemistry》2022,26(2):491-501
Journal of Solid State Electrochemistry - Grapefruit peel carbon (GPC) is prepared from waste grapefruit peel and further used as substrate for in situ construction of MoS2 arrays, forming MoS2/GPC... 相似文献
9.
Nonlinear Dynamics - Based on a mixed control strategy, this study addresses the finite-time stabilization with extended dissipativity for Markov jump systems (MJSs) with unreliable... 相似文献
10.
Achieving tunable band gaps in a structure by external stimuli is of great importance in acoustic applications. This paper aims to investigate the tunability of band gaps in square-lattice-like elastic periodic structures that are usually not featured with notable band gaps.Endowed with chirality, the periodic structures here are able to undergo imperfection-insensitive large deformation under extension or compression. The influences of geometric parameters on band gaps are discussed via the nonlinear finite element method. It is shown that the band gaps in such structures with curved beams can be very rich and, more importantly, can be efficiently and robustly tuned by applying appropriate mechanical loadings without inducing buckling. As expected, geometry plays a more significant role than material nonlinearity does in the evolution of band gaps. The dynamic tunability of band gaps through mechanical loading is further studied. Results show that closing, opening, and shifting of band gaps can be realized by exerting real-time global extension or compression on the structure. The proposed periodic structure with well-designed chiral symmetry can be useful in the design of particular acoustic devices. 相似文献