全文获取类型
收费全文 | 172754篇 |
免费 | 1859篇 |
国内免费 | 509篇 |
专业分类
化学 | 89391篇 |
晶体学 | 3057篇 |
力学 | 7200篇 |
综合类 | 3篇 |
数学 | 19658篇 |
物理学 | 55813篇 |
出版年
2020年 | 1440篇 |
2019年 | 1589篇 |
2018年 | 2014篇 |
2017年 | 2100篇 |
2016年 | 3236篇 |
2015年 | 1944篇 |
2014年 | 3180篇 |
2013年 | 7779篇 |
2012年 | 5884篇 |
2011年 | 7024篇 |
2010年 | 5120篇 |
2009年 | 5081篇 |
2008年 | 6633篇 |
2007年 | 6531篇 |
2006年 | 6160篇 |
2005年 | 5583篇 |
2004年 | 5143篇 |
2003年 | 4636篇 |
2002年 | 4483篇 |
2001年 | 5242篇 |
2000年 | 3876篇 |
1999年 | 2988篇 |
1998年 | 2493篇 |
1997年 | 2396篇 |
1996年 | 2246篇 |
1995年 | 2123篇 |
1994年 | 2107篇 |
1993年 | 2008篇 |
1992年 | 2320篇 |
1991年 | 2255篇 |
1990年 | 2203篇 |
1989年 | 2132篇 |
1988年 | 2130篇 |
1987年 | 2129篇 |
1986年 | 2025篇 |
1985年 | 2641篇 |
1984年 | 2697篇 |
1983年 | 2389篇 |
1982年 | 2503篇 |
1981年 | 2313篇 |
1980年 | 2290篇 |
1979年 | 2432篇 |
1978年 | 2468篇 |
1977年 | 2392篇 |
1976年 | 2442篇 |
1975年 | 2367篇 |
1974年 | 2332篇 |
1973年 | 2510篇 |
1972年 | 1627篇 |
1971年 | 1338篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Crosslinked poly(ethylene oxide) containing siloxanes fabricated through thiol‐ene photochemistry 下载免费PDF全文
Victor A. Kusuma Elliot A. Roth William P. Clafshenkel Steven S. Klara Xu Zhou Surendar R. Venna Erik Albenze David R. Luebke Meagan S. Mauter Richard R. Koepsel Alan J. Russell David Hopkinson Hunaid B. Nulwala 《Journal of polymer science. Part A, Polymer chemistry》2015,53(13):1548-1557
Homogenous amphiphilic crosslinked polymer films comprising of poly(ethylene oxide) and polysiloxane were synthesized utilizing thiol‐ene “ click ” photochemistry. A systematic variation in polymer composition was Carried out to obtain high quality films with varied amount of siloxane and poly(ethylene oxide). These films showed improved gas separation performance with high gas permeabilities with good CO2/N2 selectivity. Furthermore, the resulting films were also tested for its biocompatibility, as a carrier media which allow human adult mesenchymal stem cells to retain their capacity for osteoblastic differentiation after transplantation. The obtained crosslinked films were characterized using differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, FTIR, Raman‐IR , and small angle X‐ray scattering. The synthesis ease and commercial availability of the starting materials suggests that these new crosslinked polymer networks could find applications in wide range of applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1548–1557 相似文献
62.
63.
64.
65.
66.
67.
68.
69.
Following a thermal reduction method, platinum nanoparticles were synthesized and stabilized by polyvinylpyrrolidone. The colloidal platinum nanoparticles were stable for more than 3 months. The micrograph analysis unveiled that the colloidal platinum nanoparticles were well dispersed with an average size of 2.53 nm. The sol–gel‐based inverse micelle strategy was applied to synthesize mesoporous iron oxide material. The colloidal platinum nanoparticles were deposited on mesoporous iron oxide through the capillary inclusion method. The small‐angle X‐ray scattering analysis indicated that the dimension of platinum nanoparticles deposited on mesoporous iron oxide (Pt‐Fe2O3) was 2.64 nm. X‐ray photoelectron spectroscopy (XPS) data showed that the binding energy on Pt‐Fe2O3 surface decreased owing to mesoporous support–nanoparticle interaction. Both colloidal and deposited platinum nanocatalysts improved the degradation of methyl orange under reduction conditions. The activation energy on the deposited platinum nanocatalyst interface (2.66 kJ mol?1) was significantly lowered compared with the one on the colloidal platinum nanocatalyst interface (40.63 ± 0.53 kJ mol?1). 相似文献