全文获取类型
收费全文 | 97280篇 |
免费 | 802篇 |
国内免费 | 462篇 |
专业分类
化学 | 30821篇 |
晶体学 | 872篇 |
力学 | 6949篇 |
综合类 | 1篇 |
数学 | 33518篇 |
物理学 | 16544篇 |
无线电 | 9839篇 |
出版年
2023年 | 92篇 |
2022年 | 122篇 |
2021年 | 213篇 |
2020年 | 222篇 |
2019年 | 268篇 |
2018年 | 11928篇 |
2017年 | 11549篇 |
2016年 | 7311篇 |
2015年 | 1180篇 |
2014年 | 677篇 |
2013年 | 947篇 |
2012年 | 4769篇 |
2011年 | 12240篇 |
2010年 | 7247篇 |
2009年 | 7137篇 |
2008年 | 7722篇 |
2007年 | 10184篇 |
2006年 | 721篇 |
2005年 | 2097篇 |
2004年 | 2182篇 |
2003年 | 2508篇 |
2002年 | 1407篇 |
2001年 | 419篇 |
2000年 | 446篇 |
1999年 | 252篇 |
1998年 | 298篇 |
1997年 | 260篇 |
1996年 | 312篇 |
1995年 | 217篇 |
1994年 | 165篇 |
1993年 | 204篇 |
1992年 | 131篇 |
1991年 | 149篇 |
1990年 | 126篇 |
1989年 | 124篇 |
1988年 | 110篇 |
1987年 | 116篇 |
1986年 | 129篇 |
1985年 | 150篇 |
1984年 | 144篇 |
1983年 | 118篇 |
1982年 | 110篇 |
1981年 | 112篇 |
1980年 | 114篇 |
1979年 | 111篇 |
1978年 | 102篇 |
1977年 | 60篇 |
1975年 | 69篇 |
1974年 | 66篇 |
1973年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Dominik Vítek Prof. Aleš Růžička Lise Vermeersch Dr. Libor Dostál Dr. Jan Turek Prof. Roman Jambor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(70):e202202639
Reactivity studies of the GeII→B complex L(Cl)Ge⋅BH3 ( 1 ; L=2-Et2NCH2-4,6-tBu2-C6H2) were performed to determine the effect on the GeII→B donation. N-coordinated compounds L(OtBu)Ge⋅BH3 ( 2 ) and [LGe⋅BH3]2 ( 3 ) were prepared. The possible tuning of the GeII→B interaction was proved experimentally, yielding compounds 1-PPh2-8-(LGe)-C10H6 ( 4 ) and L(Cl)Ge⋅GaCl3 ( 5 ) without a GeII→B interaction. In 5 , an unprecedented GeII→Ga coordination was revealed. The experimental results were complemented by a theoretical study focusing on the bonding in 1 − 5 . The different strength of the GeII→E (E=B, Ga) donation was evaluated by using energy decomposition analysis. The basicity of different L(X)Ge groups through proton affinity is also assessed. 相似文献
2.
Golam Haider Krishna Sampathkumar Tim Verhagen Lukáš Nádvorník Farjana J. Sonia Václav Valeš Jan Sýkora Peter Kapusta Petr Němec Martin Hof Otakar Frank Yang-Fang Chen Jana Vejpravová Martin Kalbáč 《Advanced functional materials》2021,31(29):2102196
Recent advancements in isolation and stacking of layered van der Waals materials have created an unprecedented paradigm for demonstrating varieties of 2D quantum materials. Rationally designed van der Waals heterostructures composed of monolayer transition-metal dichalcogenides (TMDs) and few-layer hBN show several unique optoelectronic features driven by correlations. However, entangled superradiant excitonic species in such systems have not been observed before. In this report, it is demonstrated that strong suppression of phonon population at low temperature results in a formation of a coherent excitonic-dipoles ensemble in the heterostructure, and the collective oscillation of those dipoles stimulates a robust phase synchronized ultra-narrow band superradiant emission even at extremely low pumping intensity. Such emitters are in high demand for a multitude of applications, including fundamental research on many-body correlations and other state-of-the-art technologies. This timely demonstration paves the way for further exploration of ultralow-threshold quantum-emitting devices with unmatched design freedom and spectral tunability. 相似文献
3.
Nonlinear Dynamics - In this article, the authors simulate and study dark and bright soliton solutions of 1D and 2D regularized long wave (RLW) models. The RLW model occurred in various fields such... 相似文献
4.
In the paper, the authors establish several integral representations for the generating functions of the large and little Schröder numbers and for the large and little Schröder numbers. 相似文献
5.
Mesoscopic modeling at the pore scale offers great promise in exploring the underlying structure transport performance of flow through porous media. The present work studies the fluid flow subjected to capillarity-induced resonance in porous media characterized by different porous structure and wettability. The effects of porosity and wettability on the displacement behavior of the fluid flow through porous media are discussed. The results are presented in the form of temporal evolution of percentage saturation and displacement of the fluid front through porous media. The present study reveals that the vibration in the form of acoustic excitation could be significant in the mobilization of fluid through the porous media. The dependence of displacement of the fluid on physicochemical parameters like wettability of the surface, frequency along with the porosity is analyzed. It was observed that the mean displacement of the fluid is more in the case of invading fluid with wetting phase where the driving force strength is not so dominant. 相似文献
6.
7.
Sarah Peluse 《Israel Journal of Mathematics》2018,227(1):379-396
We prove that the group of diffeomorphisms of the interval [0, 1] contains surface groups whose action on (0, 1) has no global fix point and such that only countably many points of the interval (0, 1) have non-trivial stabiliser. 相似文献
8.
9.
10.