全文获取类型
收费全文 | 2297篇 |
免费 | 128篇 |
国内免费 | 10篇 |
专业分类
化学 | 1545篇 |
晶体学 | 4篇 |
力学 | 58篇 |
数学 | 419篇 |
物理学 | 409篇 |
出版年
2023年 | 26篇 |
2022年 | 53篇 |
2021年 | 74篇 |
2020年 | 57篇 |
2019年 | 57篇 |
2018年 | 52篇 |
2017年 | 45篇 |
2016年 | 111篇 |
2015年 | 91篇 |
2014年 | 94篇 |
2013年 | 137篇 |
2012年 | 186篇 |
2011年 | 230篇 |
2010年 | 92篇 |
2009年 | 99篇 |
2008年 | 159篇 |
2007年 | 148篇 |
2006年 | 148篇 |
2005年 | 123篇 |
2004年 | 93篇 |
2003年 | 80篇 |
2002年 | 69篇 |
2001年 | 25篇 |
2000年 | 20篇 |
1999年 | 18篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 13篇 |
1995年 | 2篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有2435条查询结果,搜索用时 15 毫秒
961.
Frontispiece: Self‐Immolative Linkers as Caps for the Design of Gated Silica Mesoporous Supports
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)
962.
963.
Pablo Ríos Dr. Josefina Díez Dr. Joaquín López‐Serrano Dr. Amor Rodríguez Dr. Salvador Conejero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(47):16791-16795
The low‐electron‐count cationic platinum complex [Pt(ItBu’)(ItBu)][BArF], 1 , interacts with primary and secondary silanes to form the corresponding σ‐SiH complexes. According to DFT calculations, the most stable coordination mode is the uncommon η1‐SiH. The reaction of 1 with Et2SiH2 leads to the X‐ray structurally characterized 14‐electron PtII species [Pt(SiEt2H)(ItBu)2][BArF], 2 , which is stabilized by an agostic interaction. Complexes 1 , 2 , and the hydride [Pt(H)(ItBu)2][BArF], 3 , catalyze the hydrosilation of CO2, leading to the exclusive formation of the corresponding silyl formates at room temperature. 相似文献
964.
Cover Picture: Probing Polyoxometalate–Protein Interactions Using Molecular Dynamics Simulations (Chem. Eur. J. 43/2016)
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)
965.
The Challenge of Deciphering Linkage Isomers in Mixtures of Oligomeric Complexes Derived from 9‐Methyladenine and trans‐(NH3)2PtII Units
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)
Dr. Susana Ibáñez Dr. Béla Mihály Dr. Pablo J. Sanz Miguel Prof. Dr. Dirk Steinborn Irene Pretzer Dr. Wolf Hiller Prof. Dr. Bernhard Lippert 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5794-5806
Metal coordination to N9‐substituted adenines, such as the model nucleobase 9‐methyladenine (9MeA), under neutral or weakly acidic pH conditions in water preferably occurs at N1 and/or N7. This leads, not only to mononuclear linkage isomers with N1 or N7 binding, but also to species that involve both N1 and N7 metal binding in the form of dinuclear or oligomeric species. Application of a trans‐(NH3)2PtII unit and restriction of metal coordination to the N1 and N7 sites and the size of the oligomer to four metal entities generates over 50 possible isomers, which display different feasible connectivities. Slowly interconverting rotamers are not included in this number. Based on 1H NMR spectroscopic analysis, a qualitative assessment of the spectroscopic features of N1,N7‐bridged species was attempted. By studying the solution behavior of selected isolated and structurally characterized compounds, such as trans‐[PtCl(9MeA‐N7)(NH3)2]ClO4 ? 2H2O or trans,trans‐[{PtCl(NH3)2}2(9MeA‐N1,N7)][ClO4]2 ? H2O, and also by application of a 9MeA complex with an (NH3)3PtII entity at N7, [Pt(9MeA‐N7)(NH3)3][NO3]2, which blocks further cross‐link formation at the N7 site, basic NMR spectroscopic signatures of N1,N7‐bridged PtII complexes were identified. Among others, the trinuclear complex trans‐[Pt(NH3)2{μ‐(N1‐9MeA‐N7)Pt(NH3)3}2][ClO4]6 ? 2H2O was crystallized and its rotational isomerism in aqueous solution was studied by NMR spectroscopy and DFT calculations. Interestingly, simultaneous PtII coordination to N1 and N7 acidifies the exocyclic amino group of the two 9MeA ligands sufficiently to permit replacement of one proton each by a bridging heterometal ion, HgII or CuII, under mild conditions in water. 相似文献
966.
967.
968.
969.
970.
Pablo Coll Javier Marenco Isabel Méndez Díaz Paula Zabala 《Annals of Operations Research》2002,116(1-4):79-90
In this paper we present a study of the polytope associated to a classic linear integer programming formulation of the graph coloring problem. We determine some families of facets. This is the initial step for the development of a branch-and-cut algorithm to solve large instances of the graph coloring problem. 相似文献