全文获取类型
收费全文 | 3994篇 |
免费 | 706篇 |
国内免费 | 553篇 |
专业分类
化学 | 2766篇 |
晶体学 | 69篇 |
力学 | 274篇 |
综合类 | 26篇 |
数学 | 596篇 |
物理学 | 1522篇 |
出版年
2024年 | 5篇 |
2023年 | 110篇 |
2022年 | 90篇 |
2021年 | 154篇 |
2020年 | 220篇 |
2019年 | 170篇 |
2018年 | 178篇 |
2017年 | 187篇 |
2016年 | 202篇 |
2015年 | 199篇 |
2014年 | 244篇 |
2013年 | 309篇 |
2012年 | 358篇 |
2011年 | 380篇 |
2010年 | 235篇 |
2009年 | 266篇 |
2008年 | 267篇 |
2007年 | 224篇 |
2006年 | 256篇 |
2005年 | 182篇 |
2004年 | 120篇 |
2003年 | 106篇 |
2002年 | 105篇 |
2001年 | 86篇 |
2000年 | 71篇 |
1999年 | 76篇 |
1998年 | 67篇 |
1997年 | 51篇 |
1996年 | 61篇 |
1995年 | 38篇 |
1994年 | 39篇 |
1993年 | 31篇 |
1992年 | 26篇 |
1991年 | 30篇 |
1990年 | 24篇 |
1989年 | 12篇 |
1988年 | 9篇 |
1987年 | 13篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1957年 | 2篇 |
1929年 | 2篇 |
1926年 | 2篇 |
排序方式: 共有5253条查询结果,搜索用时 78 毫秒
1.
Nonlinear Dynamics - Epilepsy is the second largest neurological disease which seriously threatens human life and health. The one important reason of inducing epileptic seizures is ischemic stroke... 相似文献
2.
Bingjie Chen Dr. Lianhai Zu Dr. Yao Liu Dr. Ruijing Meng Yutong Feng Prof. Chengxin Peng Feng Zhu Tianzi Hao Jiajia Ru Prof. Yonggang Wang Prof. Jinhu Yang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(8):3161-3166
Incorporating nanoscale Si into a carbon matrix with high dispersity is desirable for the preparation of lithium-ion batteries (LIBs) but remains challenging. A space-confined catalytic strategy is proposed for direct superassembly of Si nanodots within a carbon (Si NDs⊂C) framework by copyrolysis of triphenyltin hydride (TPT) and diphenylsilane (DPS), where Sn atomic clusters created from TPT pyrolysis serve as the catalyst for DPS pyrolysis and Si catalytic growth. The use of Sn atomic cluster catalysts alters the reaction pathway to avoid SiC generation and enable formation of Si NDs with reduced dimensions. A typical Si NDs⊂C framework demonstrates a remarkable comprehensive performance comparable to other Si-based high-performance half LIBs, and higher energy densities compared to commercial full LIBs, as a consequence of the high dispersity of Si NDs with low lithiation stress. Supported by mechanic simulations, this study paves the way for construction of Si/C composites suitable for applications in future energy technologies. 相似文献
3.
The research progress of a novel traffic solution,a submerged floating tunnel(SFT),is reviewed in terms of a study approach and loading scenario.Among existing publications,the buoyancy-weight ratio(BWR) is usually predefined.However,BWR is a critical structural parameter that tremendously affects the dynamic behaviour of not only the tunnel tube itself but also the cable system.In the context of a SFT prototype(SFTP) project in Qiandao Lake(Zhejiang Province,China),the importance of BWR is illustrated by finite element analysis and subsequently,an optimized BWR is proposed within a reasonable range in the present study.In the numerical model,structural damping is identified to be of importance.Rayleigh damping and the corresponding Rayleigh coefficients are attained through a sensitivity study,which shows that the adopted damping ratios are fairly suitable for SFTP.Lastly,the human sense of security is considered by quantifying the comfort index,which helps further optimize BWR in the SFTP structural parameter design. 相似文献
4.
5.
6.
7.
A new method for controlling the quantum coherence of atom laser by applying input light with strong strength is presented
within the framework of quantum dynamical theory. Unlike the case of rotating wave approximation(RWA), we show that the non-classical
properties, such as sub-Poisson distribution and quadrature squeezed effect, can appear in the output atom laser beam with
time. By choosing suitable initial RF phase, a steady and brighter output of squeezed coherent atom laser is also available. 相似文献
8.
9.
10.