全文获取类型
收费全文 | 246624篇 |
免费 | 10995篇 |
国内免费 | 1815篇 |
专业分类
化学 | 151211篇 |
晶体学 | 3781篇 |
力学 | 10925篇 |
综合类 | 10篇 |
数学 | 25138篇 |
物理学 | 68369篇 |
出版年
2021年 | 2266篇 |
2020年 | 3434篇 |
2019年 | 5284篇 |
2018年 | 4860篇 |
2017年 | 4485篇 |
2016年 | 8431篇 |
2015年 | 6029篇 |
2014年 | 7894篇 |
2013年 | 13180篇 |
2012年 | 10344篇 |
2011年 | 10871篇 |
2010年 | 9569篇 |
2009年 | 9669篇 |
2008年 | 10587篇 |
2007年 | 9898篇 |
2006年 | 8670篇 |
2005年 | 7998篇 |
2004年 | 7406篇 |
2003年 | 6783篇 |
2002年 | 7427篇 |
2001年 | 7135篇 |
2000年 | 5588篇 |
1999年 | 3607篇 |
1998年 | 2845篇 |
1997年 | 2887篇 |
1996年 | 2678篇 |
1995年 | 2311篇 |
1994年 | 2428篇 |
1993年 | 2350篇 |
1992年 | 2614篇 |
1991年 | 2709篇 |
1990年 | 2609篇 |
1989年 | 2675篇 |
1988年 | 2568篇 |
1987年 | 2590篇 |
1986年 | 2443篇 |
1985年 | 3114篇 |
1984年 | 3171篇 |
1983年 | 2639篇 |
1982年 | 2607篇 |
1981年 | 2567篇 |
1980年 | 2366篇 |
1979年 | 2725篇 |
1978年 | 2701篇 |
1977年 | 2894篇 |
1976年 | 2888篇 |
1975年 | 2686篇 |
1974年 | 2620篇 |
1973年 | 2725篇 |
1972年 | 2095篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
151.
Yablokov M. Yu. Shchegolikhin A. N. Lebedev O. V. Goncharuk G. P. Ozerin A. N. 《Russian Chemical Bulletin》2021,70(9):1816-1821
Russian Chemical Bulletin - Gradient polymer composites were prepared by melt-mixing of carbon black and polypropylene in a compounder and subsequent hot pressing of pellets. The thermally treated... 相似文献
152.
153.
Physics of Particles and Nuclei Letters - Resonance structure of the beta decay strength function Sβ(E) for GT β–-decay of halo nuclei 6He and 11Li is analyzed. Compare experimental... 相似文献
154.
Mathematical Notes - 相似文献
155.
Anishchenko V. N. Redko A. N. Rybachenko V. I. 《Theoretical and Experimental Chemistry》2020,56(1):46-49
Theoretical and Experimental Chemistry - The effect of the structure of the catalyst and the type of base on the reaction rate and product yield of the tosylation of dihydroxybenzenes in a... 相似文献
156.
Kai He Tsegaye TadesseTsega Xi Liu Jiantao Zai Xin‐Hao Li Xuejiao Liu Wenhao Li Nazakat Ali Xuefeng Qian 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):12029-12035
The modulation of electron density is an effective option for efficient alternative electrocatalysts. Here, p‐n junctions are constructed in 3D free‐standing FeNi‐LDH/CoP/carbon cloth (CC) electrode (LDH=layered double hydroxide). The positively charged FeNi‐LDH in the space‐charge region can significantly boost oxygen evolution reaction. Therefore, the j at 1.485 V (vs. RHE) of FeNi‐LDH/CoP/CC achieves ca. 10‐fold and ca. 100‐fold increases compared to those of FeNi‐LDH/CC and CoP/CC, respectively. Density functional theory calculation reveals OH? has a stronger trend to adsorb on the surface of FeNi‐LDH side in the p‐n junction compared to individual FeNi‐LDH further verifying the synergistic effect in the p‐n junction. Additionally, it represents excellent activity toward water splitting. The utilization of heterojunctions would open up an entirely new possibility to purposefully regulate the electronic structure of active sites and promote their catalytic activities. 相似文献
157.
Yamshchikov V. M. Rogachev V. G. Kudryashov E. A. Kachalin G. N. 《Optics and Spectroscopy》2020,128(8):1182-1186
Optics and Spectroscopy - The population kinetics of a two-level system has been theoretically investigated taking into account the transfer of spontaneous radiation under continuous optical... 相似文献
158.
Mejía Hugo Fernando Giraldo Jiménez-Piqué Emilio Valdés Matías Procaccini Raúl Pellice Sergio 《Journal of Solid State Electrochemistry》2020,24(10):2451-2460
Journal of Solid State Electrochemistry - A novel material was developed using sol-gel chemistry and an environmental-friendly grafting process of clay nanoparticles. In a previous work of our... 相似文献
159.
Robin F. Weitkamp Beate Neumann Hans‐Georg Stammler Berthold Hoge 《Angewandte Chemie (International ed. in English)》2020,59(14):5494-5499
We report on the first examples of isolated silanol–silanolate anions, obtained by utilizing weakly coordinating phosphazenium counterions. The silanolate anions were synthesized from the recently published phosphazenium hydroxide hydrate salt with siloxanes. The silanol–silanolate anions are postulated intermediates in the hydroxide‐mediated polymerization of aryl and alkyl siloxanes. The silanolate anions are strong nucleophiles because of the weakly coordinating character of the phosphazenium cation, which is perceptible in their activity in polysiloxane depolymerization. 相似文献