全文获取类型
收费全文 | 168篇 |
免费 | 11篇 |
专业分类
化学 | 133篇 |
晶体学 | 5篇 |
力学 | 5篇 |
数学 | 14篇 |
物理学 | 22篇 |
出版年
2016年 | 6篇 |
2015年 | 2篇 |
2014年 | 8篇 |
2013年 | 11篇 |
2012年 | 13篇 |
2011年 | 6篇 |
2010年 | 9篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2003年 | 4篇 |
2002年 | 3篇 |
1997年 | 3篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1974年 | 3篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1968年 | 5篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1959年 | 2篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1941年 | 1篇 |
1938年 | 1篇 |
1937年 | 1篇 |
1935年 | 2篇 |
1934年 | 1篇 |
1932年 | 2篇 |
1910年 | 1篇 |
1909年 | 1篇 |
1908年 | 1篇 |
1898年 | 1篇 |
1890年 | 2篇 |
1887年 | 2篇 |
1886年 | 1篇 |
1885年 | 1篇 |
1880年 | 4篇 |
排序方式: 共有179条查询结果,搜索用时 15 毫秒
51.
52.
53.
Alexander A. Kaminskii Oliver Lux Jerzy Hanuza Hanjo Rhee Hans Joachim Eichler Hitoki Yoneda Jian Zhang Dingyuan Tang Akira Shirakawa 《Laser \u0026amp; Photonics Reviews》2014,8(6):904-915
In single crystals of orthorhombic YAlO3, widely known as a host‐matrix for Ln3+‐lasant ions, many‐phonon stimulated Raman scattering interactions as well as different manifestations of cascaded and cross‐cascaded nonlinear χ(3)↔χ(3) processes are initiated by picosecond laser pulses. The scientific and applicative potential of YAlO3 crystals is considerably expanded by the demonstration of its SRS properties. In particular, the studies revealed the manifestation of eight χ(3)‐active vibrational modes. The corresponding Stokes and anti‐Stokes lines have been assigned and the steady‐state Raman gain coefficients related to the strongest phonon mode have been estimated. In addition, a short review presents the stimulated emission channels of its Ln3+‐ions together with some χ(3)‐nonlinear laser properties of crystals belonging to the binary Y2O3‐Al2O3 system. 相似文献
54.
Vincent Eschenbrenner‐Lux Dr. Heiko Dückert Dr. Vivek Khedkar Dipl.‐Chem. Hanna Bruss Prof. Dr. Herbert Waldmann Dr. Kamal Kumar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(7):2294-2304
Cascade and domino reactions that proceed through multiple steps in one pot and include multiple bond formations are promising methods for the rapid and efficient generation of complex molecular architectures, including the scaffolds of classes of complex natural product. We describe the development of various one‐pot cascade reaction sequences to yield centrocountins, which are tetracyclic indole derivatives with the basic scaffold of numerous polycyclic alkaloids. The mechanistic investigation of a sequence employing readily available alkynes and 3‐formylchromones as starting materials provided evidence that this one‐pot synthesis proceeds through at least twelve consecutive transformations and includes at least nine different chemical reactions, making it the longest cascade reaction sequence known to date. We describe the scope and limitations of the cascade synthesis approaches and the development of an enantioselectively catalyzed centrocountin synthesis. 相似文献
55.
Dr. Joachim Axhausen Dr. Karin Lux Prof. Dr. Andreas Kornath 《Angewandte Chemie (International ed. in English)》2014,53(14):3720-3721
The homogeneous mixture of anhydrous hydrogen fluoride aHF and antimony pentafluoride AsF5 is known as a superacidic system. The high acidity is derived from the formation of [H2F]+ [AsF6]?. No experimental evidence exists for the existence of the free acid molecule HAsF6. The reaction of trimethylsilyl N,N‐dimethylcarbamate in the binary system aHF/AsF5 led to decomposition of trimethylsilyl N,N‐dimethylcarbamate at ?50 °C to dimethylammonium hexafluoridoarsenate and cocrystallization of HAsF6. The single‐crystal X‐ray structure displays an HAsF6 molecule involved in an asymmetric hydrogen bridge to the hexafluoridoarsenate anion. As a result of the incalculable situation in the crystal lattice, the molecular structure of HAsF6 is calculated by quantum chemical structure optimization of the extreme cases of [FHF‐AsF5]? (strong hydrogen bond) and HAsF6 (no hydrogen bond) at the PBE1PBE/6‐311G(3df,3pd) level of theory. 相似文献
56.
Friedrich Lux 《Fresenius' Journal of Analytical Chemistry》1886,25(1):3-10
Ohne Zusammenfassung 相似文献
57.
58.
Daniel M. Lux Vivek Aryal Dr. Doleshwar Niroula Prof. Ramesh Giri 《Angewandte Chemie (International ed. in English)》2023,62(32):e202305522
We disclose a Ni-catalyzed regioselective dialkylation reaction of alkenylarenes with α-halocarbonyls and alkylzinc reagents. The reaction produces γ-arylated alkanecarbonyl compounds with the generation of two new C(sp3)−C(sp3) bonds at the vicinal carbons of alkenes. This reaction is effective for the use of primary, secondary and tertiary α-halocarboxylic esters, amides and ketones in conjunction with primary and secondary alkylzinc reagents as the sources of two C(sp3) carbons for the dialkylation of terminal and cyclic internal alkenes. 相似文献
59.
Enantiomeric Excess Sensitivity to Below One Percent by Using Femtosecond Photoelectron Circular Dichroism
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alexander Kastner Dr. Christian Lux Tom Ring Stefanie Züllighoven Cristian Sarpe Dr. Arne Senftleben Prof. Thomas Baumert 《Chemphyschem》2016,17(8):1119-1122
Photoelectron circular dichroism (PECD) is experimentally investigated with chiral specimens with varying amounts of enantiomeric excess (ee). As a prototype, we measure and analyze the photoelectron angular distribution from randomly oriented fenchone molecules in the gas phase that result from ionization with circularly polarized femtosecond laser pulses. The quantification of these measurements shows a linear dependence with respect to the ee values. In addition, differences in the ee values (denoted as detection limit) of below one percent can be distinguished for nearly enantiopure samples, as well as for almost racemates. In combination with the use of a reference, the assignment of absolute ee values is possible. The present measurement time is a few minutes, but this could be reduced. This table‐top laser‐based approach should facilitate widespread implementation in chiral analysis. 相似文献
60.
Inside Cover: Enantiomeric Excess Sensitivity to Below One Percent by Using Femtosecond Photoelectron Circular Dichroism (ChemPhysChem 8/2016)
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)