全文获取类型
收费全文 | 5175篇 |
免费 | 804篇 |
国内免费 | 570篇 |
专业分类
化学 | 3497篇 |
晶体学 | 48篇 |
力学 | 368篇 |
综合类 | 32篇 |
数学 | 683篇 |
物理学 | 1921篇 |
出版年
2024年 | 27篇 |
2023年 | 105篇 |
2022年 | 169篇 |
2021年 | 211篇 |
2020年 | 209篇 |
2019年 | 199篇 |
2018年 | 189篇 |
2017年 | 142篇 |
2016年 | 286篇 |
2015年 | 236篇 |
2014年 | 265篇 |
2013年 | 397篇 |
2012年 | 497篇 |
2011年 | 482篇 |
2010年 | 326篇 |
2009年 | 302篇 |
2008年 | 320篇 |
2007年 | 257篇 |
2006年 | 251篇 |
2005年 | 218篇 |
2004年 | 191篇 |
2003年 | 162篇 |
2002年 | 138篇 |
2001年 | 113篇 |
2000年 | 97篇 |
1999年 | 113篇 |
1998年 | 81篇 |
1997年 | 81篇 |
1996年 | 80篇 |
1995年 | 64篇 |
1994年 | 52篇 |
1993年 | 47篇 |
1992年 | 30篇 |
1991年 | 39篇 |
1990年 | 37篇 |
1989年 | 28篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 14篇 |
1985年 | 18篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1974年 | 2篇 |
1944年 | 4篇 |
1943年 | 1篇 |
1942年 | 3篇 |
1941年 | 1篇 |
1940年 | 1篇 |
排序方式: 共有6549条查询结果,搜索用时 0 毫秒
71.
72.
73.
Chunxiao Wang Yu-Xuan Chang Xi Chen Lihuan Bai Heping Wang Yu-Chen Pan Chunqiu Zhang Dong-Sheng Guo Xue Xue 《Molecules (Basel, Switzerland)》2022,27(9)
Excessive inflammatory reaction aggravates brain injury and hinders the recovery of neural function in nervous system diseases. Microglia, as the major players of neuroinflammation, control the progress of the disease. There is an urgent need for effective non-invasive therapy to treat neuroinflammation mediated by microglia. However, the lack of specificity of anti-inflammatory agents and insufficient drug dose penetrating into the brain lesion area are the main problems. Here, we evaluated a series of calixarenes and found that among them the self-assembling architecture of amphiphilic sulfonatocalix[8]arene (SC8A12C) had the most potent ability to suppress neuroinflammation in vitro and in vivo. Moreover, SC8A12C assemblies were internalized into microglia through macropinocytosis. In addition, after applying the SC8A12C assemblies to the exposed brain tissue, we observed that SC8A12C assemblies penetrated into the brain parenchyma and eliminated the inflammatory factor storm, thereby restoring neurobiological functions in a mouse model of traumatic brain injury. 相似文献
74.
75.
Hierarchical and probabilistic quantum state sharing via a non-maximally entangled stateHierarchical and probabilistic quantum state sharing via a non-maximally entangled stateHierarchical and probabilistic quantum state sharing via a non-maximally entangled state 下载免费PDF全文
A scheme that probabilistically realizes hierarchical quantum state sharing of an arbitrary unknown qubit state with a four-qubit non-maximally entangled 丨X) state is presented in this paper. In the scheme, the sender Alice distributes a quantum secret with a Bell-state measurement and publishes her measurement outcomes via a classical channel to three agents who are divided into two grades. One agent is in the upper grade, while the other two agents are in the lower grade. Then by introducing an ancillary qubit, the agent of the upper grade only needs the assistance of any one of the other two agents for probabilistically obtaining the secret, while an agent of the lower grade needs the help of both the other two agents by using a controlled-NOT operation and a proper positive operator-valued measurement instead of the usual projective measurement. In other words, the agents of two different grades have different authorities to reconstruct Alice's secret in a probabilistic manner. The scheme can also be modified to implement the threshold-controlled teleportation. 相似文献
76.
Xiaolong Shi Xiaoru Zhao Libing Duan Huinan Sun Jinming Liu Xiaojun Bai Mengmeng Guan Mengmeng Cao Jinru Liu 《Journal of Sol-Gel Science and Technology》2013,66(2):301-305
Sn-doped ZnO (SZO) thin films are deposited by sol–gel dip-coating method with Sn content at 0 at.% and 1–15 at.% with an increment of 2 at.%. The structure and luminescence of the films are investigated. X-ray diffraction results indicate that all the SZO samples show preferential orientation along the (002) direction, and the scanning electron microscope exhibits that the surface morphology of the films change from nanoparticles to nanorods with increasing Sn concentration. X-ray photoelectron spectroscopy reveals that Sn exists as valence of +4 in the matrix. The photoluminescence peaks at 381 and 398 nm are observed in all the samples. The ratio of intensity of peak at 381 nm to that of peak at 398 nm differed markedly. The intensity of peak at 398 nm might be due to the response for the Sn atoms, while the intensity of peak at 381 nm is probably related to the quantum size effect. 相似文献
77.
78.
79.
As the hardware of FLIM technique becomes mature, the most important criterion for FLIM application is the correct interpretation of its data. In this research, first of all, a more orthogonal phasor approach, called as Modified Phasor Approach (MPA), is put forward. It is a way to calculate the lifetime of the complex fluorescent process, and a rule to measure how much the fluorescence process deviates from single exponential decay. Secondly, MPA is used to analysis the time-resolved fluorescence processes of the transfected CHO-K1 Cell lines expressing adenosine receptor A1R tagged by CYP and YFP, measured in the channel of the acceptor. The image of the fluorescence lifetime and the multiplication of the fluorescence lifetime and deviation from single exponential decay reveal the details of the Homo-FRET. In one word, MPA provides the physical meaning in its whole modified phasor space, and broadens the way for the application of the fluorescence lifetime imaging. 相似文献