全文获取类型
收费全文 | 3117篇 |
免费 | 797篇 |
国内免费 | 752篇 |
专业分类
化学 | 2307篇 |
晶体学 | 123篇 |
力学 | 230篇 |
综合类 | 76篇 |
数学 | 396篇 |
物理学 | 1534篇 |
出版年
2024年 | 7篇 |
2023年 | 98篇 |
2022年 | 164篇 |
2021年 | 187篇 |
2020年 | 195篇 |
2019年 | 183篇 |
2018年 | 169篇 |
2017年 | 181篇 |
2016年 | 166篇 |
2015年 | 231篇 |
2014年 | 275篇 |
2013年 | 288篇 |
2012年 | 310篇 |
2011年 | 306篇 |
2010年 | 213篇 |
2009年 | 214篇 |
2008年 | 232篇 |
2007年 | 182篇 |
2006年 | 174篇 |
2005年 | 156篇 |
2004年 | 101篇 |
2003年 | 59篇 |
2002年 | 66篇 |
2001年 | 92篇 |
2000年 | 96篇 |
1999年 | 34篇 |
1998年 | 19篇 |
1997年 | 23篇 |
1996年 | 27篇 |
1995年 | 18篇 |
1994年 | 28篇 |
1993年 | 19篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 22篇 |
1989年 | 17篇 |
1988年 | 23篇 |
1987年 | 15篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1978年 | 5篇 |
1972年 | 1篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1959年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有4666条查询结果,搜索用时 62 毫秒
81.
82.
Jiarui Yu Nan Gao Xiaowen Xie Xing Xin Zhanqi Li Shuai Chen Jingkun Xu 《Journal of polymer science. Part A, Polymer chemistry》2022,60(5):794-802
Thermally healing capability of cracks and defects is important and urgent for the safe operation and life extending of electric materials and devices. Here, by the combination of thermally driven reversible Diels–Alder (DA) interaction and in-situ chemical oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT), a series of intrinsically conductive poly(3,4-ethylenedioxythiophene) (PEDOT)/DA composites possess intrinsically self-healing property under low-temperature (reverse DA reaction at 100°C; DA crosslinking at 60°C) stimulus were achieved. The crosslinking DA bonding reactions are multiple from the co-existence of pre-synthesized macromolecular polyurethane attached DA units (PU-DA) and 2,4-hexadiyne-1,6-diol (DADOL) in the films. PU-DA involved in the polymerization process of EDOT to endow PEDOT with outstanding solution-processability, uniform film making, and structural self-healing capability, while DADOL was added to enhance the cross bonding between polymer chains. This work will accelerate the research and application development of intrinsically self-healing conducting polymers for commercial capacitors, antistatic coatings, implantable, printable electronics, and so on. 相似文献
83.
Yu Xue Zexu Xue Wenwen Zhang Wenna Zhang Shuai Chen Kaiwen Lin Jingkun Xu 《Journal of polymer science. Part A, Polymer chemistry》2019,57(10):1041-1048
By employing planar thieno[3,2‐b]thiophene (TT) as end‐capped units and famous 3,4‐ethylenedioxythiophene (EDOT) or its all‐sulfur analog 3,4‐ethylenedithiathiophene (EDTT) as cores, two conjugated oligomer, TT‐EDOT‐TT and TT‐EDTT‐TT, have been synthesized and electropolymerized into electrochromic polymer films, P(TT‐EDOT‐TT) and P(TT‐EDTT‐TT), respectively. Due to strongly noncovalent inter/intramolecular interactions from S? S attraction of TT‐EDTT‐TT, it has twisted molecular configuration in contrast to planar TT‐EDOT‐TT. Spectroscopic, electrochemical, morphological as well as theoretical calculation studies of these oligomers or polymers were carried out to reveal the significant influence of such molecular geometry on their physicochemical and optoelectronic properties. According to electrochromic kinetics, P(TT‐EDTT‐TT) presented preferable electrochromic behavior such as the higher optical contrast (70.8%), favorable coloration efficiency (331.3 cm2 C?1) and fast response time (0.72 s). This research will help us deeply understand the effect of spatial organization of precursor molecules on the properties of electrochromic polymers and provides a promising strategy to develop high‐performance electrochromic materials. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 1041–1048 相似文献
84.
Lin-Lin Zhang Bing-Chao Da Shao-Hua Xiang Shuai Zhu Zi-Yun Yuan Zhen Guo Bin Tan 《Tetrahedron》2019,75(12):1689-1696
Quinones, precursors of aromatic structures, were firstly employed as the electrophiles for the organocatalytic Michael addition/cyclization cascade reaction with versatile 3-isothiocyanato oxindoles. Chiral bifunctional organocatalyst was appropriate for this enantioselective transformation to afford a variety of novel spirooxindoles, possessing a spirocyclic stereocenter adjacent to the aromatic ring, via asymmetric double arylation. These synthesized spirooxindoles are very difficult to access by the reported methods and were obtained in excellent chemical yields with excellent enantioselectivities. 相似文献
85.
Abduraouf Alamer Mohamed Abdurhman Yan Zhang Guoan Zhang Shuai Wang 《Analytical and bioanalytical chemistry》2015,407(26):8129-8136
86.
Cover Picture: Ultrathin Coating of Confined Pt Nanocatalysts by Atomic Layer Deposition for Enhanced Catalytic Performance in Hydrogenation Reactions (Chem. Eur. J. 25/2016)
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
87.
88.
Shuai Zhang Xiaofeng Duan Gongqing Li Kai Liu Yongqing Huang Xiaomin Ren 《Optical and Quantum Electronics》2018,50(8):320
We report a high-reflectivity non-periodic sub-wavelength gratings (SWGs) mirror with small-angle beam-steering ability for reflect light. It presents a distinctive characteristic of flexibly controlling the width of oscillation optical field for the improved Fabry–Perot (F–P) cavity. We propose a detailed principle analysis of the improved cavity. By finding out a set of SWGs with the designed structural parameters, both high reflectivity (>?93%) and beam steering (1°) can be implemented. By setting beam-steering angle and cavity length, we can control the width of oscillation optical field in the improved cavity. Beam steering ability and property of controlling the oscillation width are numerically investigated by finite element method. Simulation results prove that cavity length and steering angle can effectively control the main width of oscillation optical field, and the width is linearly associated with the cavity length. 相似文献
89.
90.