全文获取类型
收费全文 | 14043篇 |
免费 | 2549篇 |
国内免费 | 2222篇 |
专业分类
化学 | 10129篇 |
晶体学 | 214篇 |
力学 | 981篇 |
综合类 | 135篇 |
数学 | 1525篇 |
物理学 | 5830篇 |
出版年
2024年 | 24篇 |
2023年 | 235篇 |
2022年 | 352篇 |
2021年 | 486篇 |
2020年 | 587篇 |
2019年 | 552篇 |
2018年 | 485篇 |
2017年 | 483篇 |
2016年 | 671篇 |
2015年 | 741篇 |
2014年 | 882篇 |
2013年 | 1049篇 |
2012年 | 1230篇 |
2011年 | 1365篇 |
2010年 | 1024篇 |
2009年 | 896篇 |
2008年 | 1077篇 |
2007年 | 997篇 |
2006年 | 906篇 |
2005年 | 768篇 |
2004年 | 618篇 |
2003年 | 459篇 |
2002年 | 438篇 |
2001年 | 394篇 |
2000年 | 275篇 |
1999年 | 278篇 |
1998年 | 188篇 |
1997年 | 199篇 |
1996年 | 205篇 |
1995年 | 171篇 |
1994年 | 115篇 |
1993年 | 107篇 |
1992年 | 80篇 |
1991年 | 89篇 |
1990年 | 89篇 |
1989年 | 65篇 |
1988年 | 50篇 |
1987年 | 39篇 |
1986年 | 42篇 |
1985年 | 38篇 |
1984年 | 18篇 |
1983年 | 12篇 |
1982年 | 13篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1971年 | 1篇 |
1957年 | 5篇 |
1936年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 766 毫秒
11.
12.
13.
Facile non‐lithographic route to highly aligned silica nanopatterns using unidirectionally aligned polystyrene‐block‐polydimethylsiloxane films
下载免费PDF全文
![点击此处可从《Journal of Polymer Science.Polymer Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Zhe Qiang Maurice L. Wadley Bryan D. Vogt Kevin A. Cavicchi 《Journal of Polymer Science.Polymer Physics》2015,53(15):1058-1064
Thin films (monolayer and bilayer) of cylinder forming polystyrene‐block‐polydimethylsiloxane (PS‐b‐PDMS) were shear aligned by the swelling and deswelling of a crosslinked PDMS pad that was physically adhered to the film during solvent vapor annealing. The nanostructures formed by self‐assembly were exposed to ultraviolet‐ozone to partially oxidize the PDMS, followed by calcination in air at 500 °C. In this process, the PS segments were fully decomposed, while the PDMS yielded silica nanostructures. The highly aligned PDMS cylinders were thus deposited as silica nanolines on the silicon substrate. Using a bilayer film, the center‐to‐center distance of these features were effectively halved from 38 to 19 nm. Similarly, by sequential shear‐alignment of two distinct layers, a rhombic array of silica nanolines was fabricated. This methodology provides a facile route to fabricating complex topographically patterned nanostructures. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1058–1064 相似文献
14.
Jin Xie Yun-Wei Song Dr. Bo-Quan Li Dr. Hong-Jie Peng Prof. Jia-Qi Huang Prof. Qiang Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22334-22339
Polysulfide intermediates (PSs), the liquid-phase species of active materials in lithium–sulfur (Li-S) batteries, connect the electrochemical reactions between insulative solid sulfur and lithium sulfide and are key to full exertion of the high-energy-density Li-S system. Herein, the concept of sulfur container additives is proposed for the direct modification on the PSs species. By reversible storage and release of the sulfur species, the container molecule converts small PSs into large organosulfur species. The prototype di(tri)sulfide-polyethylene glycol sulfur container is highly efficient in the reversible PS transformation to multiply affect electrochemical behaviors of sulfur cathodes in terms of liquid-species clustering, reaction kinetics, and solid deposition. The stability and capacity of Li-S cells was thereby enhanced. The sulfur container is a strategy to directly modify PSs, enlightening the precise regulation on Li-S batteries and multi-phase electrochemical systems. 相似文献
15.
Summary. Let be a square matrix dependent on parameters and , of which we choose as the eigenvalue parameter. Many computational problems are equivalent to finding a point such that has a multiple eigenvalue at . An incomplete decomposition of a matrix dependent on several parameters is proposed. Based on the developed theory two new algorithms are
presented for computing multiple eigenvalues of with geometric multiplicity . A third algorithm is designed for the computation of multiple eigenvalues with geometric multiplicity but which also appears to have local quadratic convergence to semi-simple eigenvalues. Convergence analyses of these methods
are given. Several numerical examples are presented which illustrate the behaviour and applications of our methods.
Received December 19, 1994 / Revised version received January 18, 1996 相似文献
16.
17.
18.
19.
20.