全文获取类型
收费全文 | 1394篇 |
免费 | 72篇 |
国内免费 | 1篇 |
专业分类
化学 | 1033篇 |
晶体学 | 2篇 |
力学 | 24篇 |
数学 | 204篇 |
物理学 | 204篇 |
出版年
2023年 | 32篇 |
2022年 | 30篇 |
2021年 | 31篇 |
2020年 | 56篇 |
2019年 | 65篇 |
2018年 | 30篇 |
2017年 | 29篇 |
2016年 | 67篇 |
2015年 | 62篇 |
2014年 | 50篇 |
2013年 | 62篇 |
2012年 | 102篇 |
2011年 | 93篇 |
2010年 | 58篇 |
2009年 | 34篇 |
2008年 | 65篇 |
2007年 | 84篇 |
2006年 | 70篇 |
2005年 | 82篇 |
2004年 | 58篇 |
2003年 | 25篇 |
2002年 | 25篇 |
2001年 | 8篇 |
2000年 | 12篇 |
1999年 | 17篇 |
1998年 | 12篇 |
1997年 | 15篇 |
1996年 | 11篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1990年 | 6篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1983年 | 6篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1976年 | 11篇 |
1975年 | 6篇 |
1973年 | 10篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1939年 | 4篇 |
1938年 | 4篇 |
1937年 | 6篇 |
1934年 | 3篇 |
1932年 | 3篇 |
排序方式: 共有1467条查询结果,搜索用时 46 毫秒
931.
932.
Prof. Stewart F. Parker Dr. Valeri Leich Jonas Hönig Dr. Peter W. Albers 《ChemistryOpen》2020,9(10):1060-1064
For graphene to achieve its full scientific and commercial potential, reliable mass production of the material on the multi-tonne scale is essential. We have investigated five samples of graphene obtained from commercial sources that state they can supply the product on the tonne scale per annum. From electron microscopy at the micrometre to the nanometre scale, and neutron vibrational spectroscopy, we find that none of the materials examined were 100 % isolated graphene sheets. In all cases, there was a substantial content of graphite-like material. The samples exhibited varying oxygen contents, this could be present as carboxylic acid (although other oxygenates, quinones, phenols may also be present) or water. We emphasise that INS spectroscopy is particularly useful for the investigation of inorganic materials that will be used commercially: it provides atomic scale information from macroscopic (10’s of g) amounts of sample, thus ensuring that the results are truly representative. 相似文献
933.
934.
Markus Rohdenburg Martin Mayer Max Grellmann Prof. Dr. Carsten Jenne Dr. Tobias Borrmann Florian Kleemiss Priv.-Doz. Dr. Vladimir A. Azov Prof. Dr. Knut R. Asmis Prof. Dr. Simon Grabowsky Dr. Jonas Warneke 《Angewandte Chemie (International ed. in English)》2017,56(27):7980-7985
It is common and chemically intuitive to assign cations electrophilic and anions nucleophilic reactivity, respectively. Herein, we demonstrate a striking violation of this concept: The anion [B12Cl11]− spontaneously binds to the noble gases (Ngs) xenon and krypton at room temperature in a reaction that is typical of “superelectrophilic” dications. [B12Cl11Ng]− adducts, with Ng binding energies of 80 to 100 kJ mol−1, contain B−Ng bonds with a substantial degree of covalent interaction. The electrophilic nature of the [B12Cl11]− anion is confirmed spectroscopically by the observation of a blue shift of the CO stretching mode in the IR spectrum of [B12Cl11CO]− and theoretically by investigation of its electronic structure. The orientation of the electric field at the reactive site of [B12Cl11]− results in an energy barrier for the approach of polar molecules and facilitates the formation of Ng adducts that are not detected with reactive cations such as [C6H5]+. This introduces the new chemical concept of “dipole-discriminating electrophilic anions.” 相似文献
935.
936.
937.
938.
939.
940.