全文获取类型
收费全文 | 3517篇 |
免费 | 184篇 |
国内免费 | 25篇 |
专业分类
化学 | 2447篇 |
晶体学 | 18篇 |
力学 | 213篇 |
数学 | 527篇 |
物理学 | 521篇 |
出版年
2023年 | 26篇 |
2022年 | 18篇 |
2021年 | 59篇 |
2020年 | 82篇 |
2019年 | 72篇 |
2018年 | 53篇 |
2017年 | 39篇 |
2016年 | 116篇 |
2015年 | 109篇 |
2014年 | 144篇 |
2013年 | 186篇 |
2012年 | 307篇 |
2011年 | 307篇 |
2010年 | 191篇 |
2009年 | 160篇 |
2008年 | 232篇 |
2007年 | 227篇 |
2006年 | 214篇 |
2005年 | 175篇 |
2004年 | 174篇 |
2003年 | 147篇 |
2002年 | 150篇 |
2001年 | 46篇 |
2000年 | 39篇 |
1999年 | 22篇 |
1998年 | 21篇 |
1997年 | 28篇 |
1996年 | 37篇 |
1995年 | 28篇 |
1994年 | 21篇 |
1993年 | 28篇 |
1992年 | 24篇 |
1991年 | 10篇 |
1989年 | 16篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 17篇 |
1984年 | 10篇 |
1983年 | 13篇 |
1982年 | 15篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1970年 | 7篇 |
1968年 | 17篇 |
1967年 | 9篇 |
排序方式: 共有3726条查询结果,搜索用时 15 毫秒
1.
Antonin Desmecht Dr. Debobrata Sheet Claude Poleunis Prof. Sophie Hermans Prof. Olivier Riant 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(6):1436-1440
The chemical functionalization of carbon nanotubes is often a prerequisite prior to their use in various applications. The covalent grafting of 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (BPin) functional groups directly on the surface of multi- and single-walled carbon nanotubes, activated by nucleophilic addition of nBuLi, was carried out. Thermogravimetric analysis (TGA) coupled with mass spectrometry, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ions mass spectrometry (ToF-SIMS) confirmed the efficiency of this methodology and proved the integrity and covalent grafting of the BPin functional groups. These groups were further reacted with various nucleophiles in the presence of a copper(II) source in the conditions of the aerobic Chan–Lam–Evans coupling. The resulting materials were characterized by TGA, XPS and ToF-SIMS. This route is efficient, reliable and among the scarce reactions that enable the direct grafting of heteroatoms at carbonaceous material surfaces. 相似文献
2.
3.
Faure Thierry M. Dumas Laurent Montagnier Olivier 《Theoretical and Computational Fluid Dynamics》2020,34(1):79-103
Theoretical and Computational Fluid Dynamics - The aerodynamic characteristics of two neighboring airfoils are greatly different from those of a single airfoil, for both attached and detached flow... 相似文献
4.
Inside Back Cover: 9H‐Quinolino[3,2,1‐k]phenothiazine: A New Electron‐Rich Fragment for Organic Electronics (Chem. Eur. J. 50/2016) 下载免费PDF全文
5.
6.
7.
Modulation of the Physicochemical Properties of Donor–Spiro–Acceptor Derivatives through Donor Unit Planarisation: Phenylacridine versus Indoloacridine—New Hosts for Green and Blue Phosphorescent Organic Light‐Emitting Diodes (PhOLEDs) 下载免费PDF全文
Dr. Sébastien Thiery Dr. Denis Tondelier Bernard Geffroy Dr. Olivier Jeannin Dr. Joëlle Rault‐Berthelot Dr. Cyril Poriel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(29):10136-10149
This work reports a detailed structure–property relationship study of a series of efficient host materials based on the donor–spiro–acceptor (D‐spiro‐A) design for green and sky‐blue phosphorescent organic light‐emitting diodes (PhOLEDs). The electronic and physical effects of the indoloacridine (IA) fragment connected through a spiro bridge to different acceptor units, namely, fluorene, dioxothioxanthene or diazafluorene moiety, have been investigated in depth. The resulting host materials have been easily synthesised through short, efficient, low‐cost, and highly adaptable synthetic routes by using common intermediates. The dyes possess a very high triplet energy (ET) and tuneable HOMO/LUMO levels, depending on the strength of the donor/acceptor combination. The peculiar electrochemical and optical properties of the IA moiety have been investigated though a fine comparison with their phenylacridine counterparts to study the influence of planarisation. Finally, these molecules have been incorporated as hosts in green and sky‐blue PhOLEDs. For the derivative SIA‐TXO2 as a host, external quantum efficiencies as high as 23 and 14 % have been obtained for green and sky‐blue PhOLEDs, respectively. 相似文献
8.
9.
10.