全文获取类型
收费全文 | 435篇 |
免费 | 28篇 |
专业分类
化学 | 296篇 |
晶体学 | 3篇 |
力学 | 10篇 |
数学 | 24篇 |
物理学 | 130篇 |
出版年
2023年 | 6篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 19篇 |
2017年 | 8篇 |
2016年 | 17篇 |
2015年 | 7篇 |
2014年 | 20篇 |
2013年 | 24篇 |
2012年 | 32篇 |
2011年 | 34篇 |
2010年 | 25篇 |
2009年 | 12篇 |
2008年 | 21篇 |
2007年 | 21篇 |
2006年 | 11篇 |
2005年 | 15篇 |
2004年 | 12篇 |
2003年 | 3篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1988年 | 2篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 9篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1967年 | 3篇 |
1939年 | 2篇 |
排序方式: 共有463条查询结果,搜索用时 15 毫秒
371.
372.
373.
Jingjing Cui Dr. Yongxin Li Dr. Rakesh Ganguly Prof. Dr. Rei Kinjo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(29):9976-9985
The reactivity of diazadiphosphapentalene 1 towards various substrates was investigated. Reaction of 1 with ammonia–borane resulted in transfer hydrogenolysis concomitantly with the cleavage of a P?N bond. By treatment of 1 with 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO), oxidation took place at one of the phosphorus atoms of 1 , and a PV/PIII mixed‐valence derivative was isolated. At the same time, it was demonstrated that only one of the phosphorus atoms in 1 behaves as an electron donor for electrophiles and Lewis acids. The former afforded an intramolecularly coordinated phosphine‐phosphenium species, whereas the latter demonstrates the ligand property of 1 . UV irradiation induced rearrangement of 1 into another example of another diazadiphosphapentalene. 相似文献
374.
375.
Isolation of an Imino‐N‐heterocyclic Carbene/Germanium(0) Adduct: A Mesoionic Germylene Equivalent
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bochao Su Dr. Rakesh Ganguly Dr. Yongxin Li Prof. Dr. Rei Kinjo 《Angewandte Chemie (International ed. in English)》2014,53(48):13106-13109
An autoionization of germanium dichloride/dioxane complex with an imino‐N‐heterocyclic carbene ligand ( L ) afforded a novel germyliumylidene ion, [( L )GeCl]+[GeCl3]?, which was fully characterized. Reduction of the germyliumylidene ion with potassium graphite produced a cyclic species [( L )Ge], which can be viewed as both a Ge0 species and a mesoionic germylene. X‐ray diffraction analysis and computational studies revealed one of the lone pairs on the Ge atom is involved in the π system on the GeC2N2 five‐membered ring. It was also confirmed that the nucleophilic behavior of [( L )Ge] as a two lone‐pair donor. 相似文献
376.
Laxmaiah Vasamsetty Debashis Sahu Bishwajit Ganguly Faiz Ahmed Khan Goverdhan Mehta 《Tetrahedron》2014
A short and generally applicable synthesis of bioactive tetracyclic natural product paracaseolide A has been accomplished employing a ‘proposed’ biomimetic Diels–Alder reaction as the key strategic step. The Diels–Alder precursors for this purpose were readily assembled through a versatile Suzuki coupling on preformed α-halo butenolides. The mechanistic aspects of the ‘putative’ biomimetic Diels–Alder reaction have been probed using computational methods, which suggest that this [4+2]-cycloaddition proceeds through a step-wise process and product profile is thermodynamically governed. 相似文献
377.
A Well‐Defined Aluminum‐Based Lewis Acid as an Effective Catalyst for Diels–Alder Transformations
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)
Zhizhou Liu Jazreen Hui Qi Lee Dr. Rakesh Ganguly Dr. Dragoslav Vidović 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(32):11344-11348
A catalytically active aluminum‐based system for Diels–Alder transformations is reported. The system was generated by mixing a β‐diketiminate‐stabilized aluminum bistriflate compound with Na[BArCl4] (ArCl=3,5‐Cl2C6H3). Solid‐state analysis of the catalytic system reveals a unique structure incorporating a two‐dimensional coordination polymer. According to the experimental results obtained from several Diels–Alder transformations, the aluminum‐based system appears to be a more practical and more robust alternative to the recently reported compounds based on carbon and silicon cations. 相似文献
378.
379.
The bubble model, which is conventionally used to fit the observed characteristics of the pickoff component of ortho-Positronium decay in liquids, is subjected in this study to a critical assessment. It is demonstrated that in its present form (namely that of a bubble with a sharp boundary) the model is untenable when confronted jointly with experimental data on the lifetime and angular correlation of the decay gammas. A modified version of the model, free from such shortcomings, is presented. Further, the dramatic turnover in the temperature dependence of the rate for the formation of positronium–acceptor complex in the case of nitro-benzene in different solvents is interpreted as a Kramers’ turnover in the context of the improved Bubble Model. 相似文献
380.
Ajay K. Bose Maghar S. Manhas Subhendu N. Ganguly Suhas Pednekar Arun Mandadi 《Tetrahedron letters》2005,46(17):3011-3013
A water-based biphasic reaction process has been developed for conducting exothermic reactions without organic solvents. This procedure is rapid, simple, and suitable for small scale synthesis as well as larger (multi-molar) scale reactions. The preparation of several hundred grams of clofibric acid and analogues by this eco-friendly and energy-efficient procedure is described. Smaller amounts of these compounds were prepared by the friction-activated ‘Grindstone Chemistry’ method described previously. 相似文献