全文获取类型
收费全文 | 1041篇 |
免费 | 53篇 |
国内免费 | 6篇 |
专业分类
化学 | 909篇 |
晶体学 | 3篇 |
力学 | 22篇 |
数学 | 27篇 |
物理学 | 139篇 |
出版年
2023年 | 13篇 |
2022年 | 6篇 |
2021年 | 15篇 |
2020年 | 29篇 |
2019年 | 18篇 |
2018年 | 13篇 |
2017年 | 8篇 |
2016年 | 24篇 |
2015年 | 19篇 |
2014年 | 28篇 |
2013年 | 30篇 |
2012年 | 47篇 |
2011年 | 67篇 |
2010年 | 26篇 |
2009年 | 33篇 |
2008年 | 48篇 |
2007年 | 49篇 |
2006年 | 62篇 |
2005年 | 66篇 |
2004年 | 49篇 |
2003年 | 30篇 |
2002年 | 49篇 |
2001年 | 44篇 |
2000年 | 29篇 |
1999年 | 19篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 18篇 |
1991年 | 13篇 |
1990年 | 17篇 |
1989年 | 14篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 13篇 |
1984年 | 5篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1979年 | 15篇 |
1977年 | 8篇 |
1976年 | 12篇 |
1975年 | 6篇 |
1974年 | 15篇 |
1973年 | 9篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1967年 | 7篇 |
排序方式: 共有1100条查询结果,搜索用时 15 毫秒
71.
Inside Cover: Enhancement of Light Absorption Ability of Synthetic Chlorophyll Derivatives by Conjugation with a Difluoroboron Diketonate Group (Chem. Eur. J. 29/2016)
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
72.
73.
Utilization of a metalloligand, ([Cu(2,4-pydca)2(H2O)].2Et3NH) (1) (2,4-pydca = pyridine-2,4-dicarboxylate), as a building unit provides a novel porous coordination polymer, ([ZnCu(2,4-pydca)2(H2O)3(DMF)].DMF)n (2), in which the Zn(II) ion at the node of the network acts as a linker and the Cu(II) ion in the channel wall is available for guest-coordination. 相似文献
74.
75.
[reaction: see text] Radical cascade reaction with various 1,4-dienes and 1,4-enynes using dimethyl 2-(iodomethyl)cyclopropane-1,1-dicarboxylate as a homoallyl radical precursor smoothly proceeds through an iodine atom transfer mechanism to give functionalized bicyclo[3.3.0]octane derivatives in good yields. 相似文献
76.
77.
Kitagawa K Inoue A Shinokubo H Oshima K 《Angewandte Chemie (International ed. in English)》2000,39(14):2481-2483
78.
7-Ethynylcycloheptatriene (1) cleanly isomerizes to phenylallene in the presence of acid. A mechanism involving the protonation of ethynylnorcaradiene, which is in equilibrium with 1, followed by the cleavage of a three-membered ring to give an arenium ion, is proposed. The rearrangement is accelerated by a factor of 370 by introducing tert-butyl groups on C-2 and C-5, indicating the importance of the equilibrium concentration of the norcaradiene form as a rate-controlling factor. 相似文献
79.
Tamotsu Kamiya Kuniyuki Goto Isao Shinohara 《Journal of polymer science. Part A, Polymer chemistry》1979,17(2):561-569
The ionene polymers were prepared by the Menshutkin reaction of α,ω-dibromoalkane (n) with triethylenediamine (TDA) or 4,4′-bipyridil (BP). Resistivities (p) and activation energies of conduction (Ea) were measured for the polymeric 7,7,8,8-tetracyanoquinodimethan (TCNQ) salts with these ionenes. The correlation between the chemical structure of the ionenes and the conductivity was discussed. In the TDA,n-TCNQ complex salts and the BP,n-TCNQ simple salts the salts of the ionenes containing even numbers of CH2 groups showed higher conductivities than those of the ionenes containing odd numbers of CH2 groups. The conductivities determined by the narrower interval between the N+ cations of the main chains were measured in the simple salts. In the complex salts the conductivities determined by the larger interval were measured. The conformational change of the matrix ionenes affected the arrangement of the TCNQ molecules. The values of p were 79.7 and 12.5 Ω cm, and the values of Ea were 0.122 and 0.063 eV for TDA,4-TCNQ complex salt and BP,5-TCNQ complex salt, respectively. 相似文献
80.