全文获取类型
收费全文 | 32456篇 |
免费 | 240篇 |
国内免费 | 285篇 |
专业分类
化学 | 12772篇 |
晶体学 | 315篇 |
力学 | 1454篇 |
综合类 | 15篇 |
数学 | 9563篇 |
物理学 | 8862篇 |
出版年
2021年 | 97篇 |
2020年 | 98篇 |
2019年 | 119篇 |
2018年 | 1292篇 |
2017年 | 1555篇 |
2016年 | 867篇 |
2015年 | 689篇 |
2014年 | 617篇 |
2013年 | 976篇 |
2012年 | 3356篇 |
2011年 | 2542篇 |
2010年 | 1966篇 |
2009年 | 1681篇 |
2008年 | 718篇 |
2007年 | 759篇 |
2006年 | 695篇 |
2005年 | 4503篇 |
2004年 | 3969篇 |
2003年 | 2379篇 |
2002年 | 560篇 |
2001年 | 357篇 |
2000年 | 133篇 |
1999年 | 212篇 |
1998年 | 157篇 |
1997年 | 100篇 |
1996年 | 71篇 |
1995年 | 75篇 |
1994年 | 83篇 |
1993年 | 48篇 |
1992年 | 203篇 |
1991年 | 173篇 |
1990年 | 162篇 |
1989年 | 140篇 |
1988年 | 127篇 |
1987年 | 79篇 |
1986年 | 59篇 |
1985年 | 72篇 |
1984年 | 60篇 |
1983年 | 54篇 |
1982年 | 44篇 |
1979年 | 58篇 |
1978年 | 54篇 |
1976年 | 112篇 |
1975年 | 57篇 |
1974年 | 71篇 |
1973年 | 70篇 |
1972年 | 51篇 |
1969年 | 47篇 |
1968年 | 46篇 |
1966年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 421 毫秒
991.
992.
Mileva Prvanovi? 《Journal of Geometry》2012,103(1):89-101
We consider an almost Hermitian manifold and apply the conformal change of metric to its holomorphic curvature tensor. In such a way we find that the generalized Bochner curvature tensor can be expressed as a linear combination of B 1, B 2, and B 3 such that (6.4) holds. Each of the tensors B 1, B 2, B 3 is conformally invariant and satisfies the condition (1.2) of K?hler type. 相似文献
993.
M. D?ring U. -G. Mei?ner E. Oset A. Rusetsky 《The European Physical Journal A - Hadrons and Nuclei》2012,48(8):1-18
Phase shifts and resonance parameters can be obtained from finite-volume lattice spectra for interacting pairs of particles, moving with non-zero total momentum. We present a simple derivation of the method that is subsequently applied to obtain the ?Ц? and ??K phase shifts in the sectors with total isospin I = 0 and I = 1/2 , respectively. Considering different total momenta, one obtains extra data points for a given volume that allow for a very efficient extraction of the resonance parameters in the infinite-volume limit. Corrections due to the mixing of partial waves are provided. We expect that our results will help to optimize the strategies in lattice simulations, which aim at an accurate determination of the scattering and resonance properties. 相似文献
994.
995.
996.
Nina I. Simirskaya Nikolai V. Ignat’ev Michael Schulte Sergei G. Zlotin 《Mendeleev Communications》2012,22(6):317-319
Terminal alkynols react with formaldehyde and secondary amines in aqueous ionic liquid [emim]HSO–4 in the presence of Cu(OAc) to afford the corresponding 1-(a-hydroxyalkyl)- or 1-(b-hydroxyalkyl)-2-(aminomethyl)acetylenes in better yields in comparison with the reaction in conventional organic solvents. The catalytic system can be easily recovered and recycled. 相似文献
997.
Vít Kremláček Erik Kertész Prof. Zoltán Benkő Milan Erben Robert Jirásko Prof. Aleš Růžička Prof. Roman Jambor Prof. Libor Dostál 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(52):13096-13097
Invited for the cover of this issue are Zoltán Benkő, Libor Dostál and co-workers at the University of Pardubice and the Budapest University of Technology and Economics. The image depicts signs for the two different pathways representing the two differing reaction types which were clearly observed for 2,1-benzazaphosphole. Read the full text of the article at 10.1002/chem.202101686 . 相似文献
998.
Maja Trček George Cordoyiannis Brigita Rožič Vassilios Tzitzios George Nounesis Samo Kralj 《Liquid crystals》2017,44(10):1575-1581
We report on the stabilisation of the liquid-crystalline, twist-grain boundary A (TGBA) phase in mixtures of a chiral liquid crystal and surface-functionalised spherical Au nanoparticles (NPs) of 10 nm diameter. The results, obtained by calorimetric, optical, small-angle X-ray and plasmon resonance measurements, demonstrate that a TGBA phase, which is metastable for the pure liquid crystal host, can be effectively stabilised for a 3 K range in the presence of NPs. Moreover, the role of NPs size on the TGBA stabilisation is briefly discussed. 相似文献
999.
1000.
Jagodič M. Vakulka A. Goreshnik E. Jagličić Z. Trontelj Z. 《Theoretical and Experimental Chemistry》2021,57(5):366-370
Theoretical and Experimental Chemistry - The magnetochemical behavior of the cis-[CuCl2(DMSO)2] complex was analyzed. cis-Complex crystals were found to be perfectly paramagnetic above 50 K and... 相似文献