全文获取类型
收费全文 | 7929篇 |
免费 | 1228篇 |
国内免费 | 925篇 |
专业分类
化学 | 5650篇 |
晶体学 | 100篇 |
力学 | 486篇 |
综合类 | 57篇 |
数学 | 944篇 |
物理学 | 2845篇 |
出版年
2024年 | 18篇 |
2023年 | 157篇 |
2022年 | 161篇 |
2021年 | 263篇 |
2020年 | 290篇 |
2019年 | 325篇 |
2018年 | 240篇 |
2017年 | 238篇 |
2016年 | 348篇 |
2015年 | 386篇 |
2014年 | 420篇 |
2013年 | 519篇 |
2012年 | 698篇 |
2011年 | 780篇 |
2010年 | 468篇 |
2009年 | 416篇 |
2008年 | 486篇 |
2007年 | 450篇 |
2006年 | 442篇 |
2005年 | 367篇 |
2004年 | 283篇 |
2003年 | 246篇 |
2002年 | 209篇 |
2001年 | 181篇 |
2000年 | 190篇 |
1999年 | 201篇 |
1998年 | 177篇 |
1997年 | 160篇 |
1996年 | 158篇 |
1995年 | 140篇 |
1994年 | 130篇 |
1993年 | 90篇 |
1992年 | 82篇 |
1991年 | 100篇 |
1990年 | 65篇 |
1989年 | 42篇 |
1988年 | 34篇 |
1987年 | 33篇 |
1986年 | 26篇 |
1985年 | 21篇 |
1984年 | 10篇 |
1983年 | 19篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1971年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 23 毫秒
991.
Xia X Zeng J McDearmon B Zheng Y Li Q Xia Y 《Angewandte Chemie (International ed. in English)》2011,50(52):12542-12546
Shaped and dimpled: Silver nanocrystals enclosed by concave surfaces and thus high-index facets have been prepared by simply controlling the growth habit of Ag cubic seeds. Four types of concave nanocrystals, including octahedron, cube, octapod, and trisoctahedron, were obtained (see picture). 相似文献
992.
Quanyi Hao Danni Lei Xiaoming Yin Ming Zhang Shuang Liu Qiuhong Li Libao Chen Taihong Wang 《Journal of Solid State Electrochemistry》2011,15(11-12):2563-2569
Urchin-like nano/micro-structured Fe3O4/C composite has been successfully synthesized using inexpensive starting materials. The urchin-shaped nano/micro-structure consisted of several oriented nanorods. TEM analysis revealed that there is a large number of pores and uniform amorphous carbon distribution at a nanoscale in the nanorods walls. As used in lithium-ion batteries, the mesoporous Fe3O4/C anode delivered a higher reversible capacity of about 830?mAh?g?1 at 0.1?C up to 50 cycles, as well as enhanced high-rate capability compared with urchin-like Fe2O3 and commercial Fe3O4. The improvements can be attributed to the combined effects of the nano/micro-architecture, the porosity, and the ultra-fine carbon matrix, where the three factors would contribute to possess both the merits of nanometer-sized building blocks and micro-sized assemblies and provide high electronic conductivity. It is believed that the results of this study offer new prospects for improving the lithium storage capacity of metal oxides by controlling both architecture and composition. 相似文献
993.
994.
995.
996.
The intermolecular interactions in C6H6???LiX (X=OH, NH2, F, Cl, Br, NC, CN) complexes are investigated by using second‐order Møller–Plesset perturbation theory (MP2) calculations and quantum theory of “atoms in molecules” (QTAIM) studies, and the role of π electrons is studied in the formation of these benzene‐containing lithium‐bonded complexes. The molecular electrostatic potentials of benzene and LiX determine the geometries of the lithium‐bonded complexes. The electron densities at the lithium bond critical points in the πC6H6???LiX complexes are obviously stronger than those in the σC6H6???LiX complexes, which indicates that the intermolecular interactions in the C6H6???LiX complexes are mainly attributable to π‐type interaction. The topological and energy properties at the lithium bond critical points in both the C6H6???LiX and πC6H6???LiX complexes are linear with the interaction energies, thereby showing the crucial role of the π electrons in the formation of these complexes. Electron localization function (ELF) analysis indicates that the formation of the lithium bonds leads to the reduction of the ELF π‐electron density and volume, and the reduction of the π‐electron volume is linear with the interaction energies with the correction coefficient 0.9949. 相似文献
997.
998.
999.
1000.