全文获取类型
收费全文 | 715篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
化学 | 388篇 |
晶体学 | 3篇 |
力学 | 48篇 |
数学 | 156篇 |
物理学 | 131篇 |
出版年
2023年 | 3篇 |
2022年 | 19篇 |
2021年 | 30篇 |
2020年 | 9篇 |
2019年 | 19篇 |
2018年 | 12篇 |
2017年 | 6篇 |
2016年 | 37篇 |
2015年 | 21篇 |
2014年 | 26篇 |
2013年 | 46篇 |
2012年 | 36篇 |
2011年 | 38篇 |
2010年 | 27篇 |
2009年 | 17篇 |
2008年 | 25篇 |
2007年 | 39篇 |
2006年 | 35篇 |
2005年 | 39篇 |
2004年 | 32篇 |
2003年 | 16篇 |
2002年 | 18篇 |
2001年 | 13篇 |
2000年 | 6篇 |
1999年 | 11篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1977年 | 6篇 |
1975年 | 3篇 |
1968年 | 2篇 |
1928年 | 2篇 |
1915年 | 2篇 |
1905年 | 2篇 |
排序方式: 共有726条查询结果,搜索用时 15 毫秒
721.
Letters in Mathematical Physics - We provide an algorithm that factorizes one-dimensional quantum walks on an arbitrary but fixed cell structure into a protocol of two basic operations: a fixed... 相似文献
722.
Francesca D'Anna Vincenzo Frenna Susanna Guernelli Gabriella Macaluso Salvatore Marullo Domenico Spinelli 《Journal of Physical Organic Chemistry》2008,21(4):306-314
A kinetic investigation in methanol of the title reaction has evidenced the occurrence of two processes: the 1‐ E 1‐ Z isomerization and the rearrangement of the (Z)‐isomer into the relevant 4‐benzoylamino‐2,5‐diphenyl‐1,2,3‐triazole ( 1‐ Z → T ). The latter reaction is in line with the ability of the (Z)‐phenylhydrazones of 3‐benzoyl‐1,2,4‐oxadiazoles to undergo the so called mononuclear rearrangement of heterocycles (MRH). The occurrence of both the examined reactions is dependent on a Lewis‐acid‐catalysis. The obtained results have shown the possibility of a ‘new’ type of acid‐catalysis (bifunctional catalysis by Lewis salts) in the MRH. This catalysis operates through a completely different mechanism with respect to the one recently observed, and deeply investigated, in the presence of protic acids for the (Z)‐phenylhydrazone of 5‐amino‐3‐benzoyl‐1,2,4‐oxadiazole, in both dioxane/water and toluene, for which the catalytic process was dependent on the protonation of N(4) ring‐nitrogen of the 1,2,4‐oxadiazole. As a matter of fact, the copper salts seem able to interact with the >C?N? NH? C6H5 moiety, yielding adducts which, in some cases, are prone to both isomerize and rearrange. Therefore, a similar behaviour in some manner parallel to that already observed in benzene in the presence of aliphatic amines (base‐catalysis) has been evidenced. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
723.
F. Ambrosino A. Antonelli M. Antonelli F. Archilli P. Beltrame G. Bencivenni C. Bini C. Bloise S. Bocchetta F. Bossi P. Branchini G. Capon D. Capriotti T. Capussela F. Ceradini P. Ciambrone E. De Lucia A. De Santis P. De Simone G. De Zorzi A. Denig A. Di Domenico C. Di Donato B. Di Micco M. Dreucci G. Felici S. Fiore P. Franzini C. Gatti P. Gauzzi S. Giovannella E. Graziani M. Jacewicz V. Kulikov G. Lanfranchi J. Lee-Franzini M. Martini P. Massarotti S. Meola S. Miscetti M. Moulson S. Müller F. Murtas M. Napolitano F. Nguyen M. Palutan A. Passeri V. Patera P. Santangelo B. Sciascia A. Sibidanov T. Spadaro L. Tortora P. Valente G. Venanzoni R. Versaci 《The European Physical Journal C - Particles and Fields》2010,65(3-4):703-703
724.
Alice Benzi Lara Bianchi Gianluca Giorgi Massimo Maccagno Giovanni Petrillo Domenico Spinelli Cinzia Tavani 《Molecules (Basel, Switzerland)》2022,27(10)
Nitrostilbenes characterized by two different or differently substituted aryl moieties can be obtained from the initial ring-opening of 3-nitrobenzo[b]thiophene with amines. Such versatile building blocks couple the well-recognized double electrophilic reactivity of the nitrovinyl moiety (addition to the double bond, followed by, e.g., intramolecular replacement of the nitro group) with the possibility to exploit a conjugated system of double bonds within an electrocyclization process. Herein, nitrostilbenes are reacted with different aromatic enols provided by a double (carbon and oxygen) nucleophilicity, leading to novel, interesting naphthodihydrofurans. From these, as a viable application, aromatization and electrocyclization lead in turn to valuable polycondensed, fully aromatic O-heterocycles. 相似文献
725.
The principal features of the volumetric as well as the viscoelastic response of mechanically stimulated glasses can be summarized as follows: i) the time-aging time shift factors contract upon increasing the probe stress (i.e. the stress apparently modifies the volume recovery kinetics), ii) the volume recovery baseline remains unaltered (i.e. the underlying structure of the stimulated glass remains unchanged) iii) yielding scales linearly with the logarithmic of the strain rate. Here we present a review of the above features with aid of a series of numerically simulated results concerning the responses of glassy polycarbonate. Simulations are obtained coupling a modified KAHR equation with the constitutive law for linear viscoelasticity within the domain of the reduced time. It will be shown that by using a minimum of experimental (PVT and linear viscoelastic) data inputs even the subtle intricacies can be predicted. Furthermore a new class of results concerning the stress-strain behaviour of glassy polymers is presented that never appeared before. 相似文献
726.