全文获取类型
收费全文 | 8276篇 |
免费 | 265篇 |
国内免费 | 4篇 |
专业分类
化学 | 3982篇 |
晶体学 | 62篇 |
力学 | 209篇 |
数学 | 1830篇 |
物理学 | 2293篇 |
无线电 | 169篇 |
出版年
2021年 | 94篇 |
2020年 | 127篇 |
2019年 | 110篇 |
2018年 | 164篇 |
2017年 | 156篇 |
2016年 | 331篇 |
2015年 | 299篇 |
2014年 | 334篇 |
2013年 | 601篇 |
2012年 | 414篇 |
2011年 | 484篇 |
2010年 | 296篇 |
2009年 | 257篇 |
2008年 | 282篇 |
2007年 | 243篇 |
2006年 | 175篇 |
2005年 | 80篇 |
2004年 | 121篇 |
2003年 | 129篇 |
2002年 | 128篇 |
2001年 | 120篇 |
2000年 | 132篇 |
1999年 | 113篇 |
1998年 | 111篇 |
1997年 | 103篇 |
1996年 | 90篇 |
1995年 | 83篇 |
1994年 | 87篇 |
1993年 | 80篇 |
1992年 | 85篇 |
1991年 | 74篇 |
1990年 | 85篇 |
1989年 | 72篇 |
1988年 | 77篇 |
1987年 | 72篇 |
1986年 | 66篇 |
1985年 | 98篇 |
1984年 | 110篇 |
1983年 | 71篇 |
1982年 | 88篇 |
1981年 | 96篇 |
1980年 | 80篇 |
1979年 | 96篇 |
1978年 | 88篇 |
1977年 | 79篇 |
1976年 | 100篇 |
1975年 | 96篇 |
1974年 | 91篇 |
1973年 | 71篇 |
1968年 | 74篇 |
排序方式: 共有8545条查询结果,搜索用时 500 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.
Zakrajšek Srečko Rajkovič Vladislav Bernik Mojca Jereb Eva Rajkovič Uroš 《Central European Journal of Operations Research》2021,29(3):841-857
Central European Journal of Operations Research - Digital competences are among the most important competences in modern society, with the education system playing a key role in the acquisition of... 相似文献
4.
5.
6.
Nováková Kateřina Hrdlička Vojtěch Navrátil Tomáš Vyskočil Vlastimil Barek Jiří 《Monatshefte für Chemie / Chemical Monthly》2015,146(5):761-769
Monatshefte für Chemie - Chemical Monthly - The voltammetric behavior of 5-nitroindazole was investigated at polished (p-AgSAE) and at mercury meniscus-modified (m-AgSAE) silver solid amalgam... 相似文献
7.
Tanja Vidaković-Koch Tamara Miličić Luka A. Živković Hoon Seng Chan Ulrike Krewer Menka Petkovska 《Current Opinion in Electrochemistry》2021
The nonlinear frequency response analysis (NFRA) can be seen as an extension of electrochemical impedance spectroscopy. NFRA gives a full and detailed representation of the system response and can establish a connection between model parameters and the experimentally observed phenomena. In this article, different theoretical NFRA approaches and the most recent application examples are discussed. A simple electrochemical example is used to showcase the benefits and disadvantages of analyzing the system response by using different approaches. In addition, it was shown how to extract experimental harmonic values and analyze them. 相似文献
8.
9.
Separation of 23 dansylated amino acids by micellar electrokinetic chromatography at low temperature
Summary The baseline separation of 23 dansylated amino acids (including 3 didansylated species) is reported. Lowering of the analysis
temperature and fine control of the surfactant concentration were essential in obtaining this result. Calibration graphs with
good linearity were obtained. 相似文献
10.