全文获取类型
收费全文 | 993篇 |
免费 | 22篇 |
国内免费 | 6篇 |
专业分类
化学 | 662篇 |
晶体学 | 5篇 |
力学 | 45篇 |
数学 | 127篇 |
物理学 | 182篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 25篇 |
2020年 | 17篇 |
2019年 | 29篇 |
2018年 | 31篇 |
2017年 | 17篇 |
2016年 | 40篇 |
2015年 | 26篇 |
2014年 | 34篇 |
2013年 | 81篇 |
2012年 | 57篇 |
2011年 | 76篇 |
2010年 | 57篇 |
2009年 | 37篇 |
2008年 | 66篇 |
2007年 | 49篇 |
2006年 | 63篇 |
2005年 | 65篇 |
2004年 | 54篇 |
2003年 | 35篇 |
2002年 | 34篇 |
2001年 | 13篇 |
2000年 | 17篇 |
1999年 | 10篇 |
1998年 | 11篇 |
1997年 | 15篇 |
1996年 | 13篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1021条查询结果,搜索用时 15 毫秒
51.
Structural Chemistry - Milestones of historical evolution of the Chemistry Department of the Lomonosov Moscow State University, which was formally separated from the physical-mathematical faculty... 相似文献
52.
53.
54.
Alexey Bobrovsky Valery Shibaev Martin Cigl Vra Hamplov Vladimíra Novotn 《Journal of Polymer Science.Polymer Physics》2019,57(19):1337-1342
New photochromic polymethacrylates with different spacer length having azobenzene side groups and lateral methyl substituents were synthesized. The phase behavior of polymethacrylates and their photooptical properties were studied and compared with unsubstituted analogues. It is shown that an introduction of lateral methyl substituents results in almost complete suppression of liquid crystalline (LC) phase formation and strong decrease of photoinduced dichroism values. It is found that rates of the photoinduced E‐Z isomerization and back thermal Z‐E isomerization are almost independent on spacer lengths. Due to the presence of lateral substituents, the photoinduced azobenzene Z‐form shows remarkable long lifetime, and back thermal conversion at room temperature takes more than 10 days. Specific peculiarities of the photoorientation process in polymer films under the polarized UV and visible light action were studied and their mechanism is suggested. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1337–1342 相似文献
55.
Jitendra Gurjar Prof. Dr. Valery V. Fokin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(46):10402-10405
A metal-free and redox-neutral method for Beckmann rearrangement employing inexpensive and readily available SO2F2 gas is described. The reported transformation proceeds at ambient temperature and is compatible with a wide range of sterically and electronically diverse aromatic, heteroaromatic, aliphatic and lignin-like oximes providing amides in good to excellent yields. The reaction proceeds through the formation of an imidoyl fluoride intermediate that can also be used for the synthesis of amidines. 相似文献
56.
Valery L. Okulov 《Regular and Chaotic Dynamics》2016,21(3):267-273
The aim of this paper is to test the possibility of a secondary solution of the acentric rotation of helical vortex pairs with the same pitch, sign and strength. The investigation addresses the three-dimensional vortex dynamics of thin vortex filaments. As a result of the current investigation, this secondary solution with acentric vortex positions in the helical pairs is found. This fact was not discussed in previous studies, and the existence of the new equilibrium solution for the helical vortex pairs is an original result. 相似文献
57.
58.
59.
Shestakova Tatyana S. Deev Sergey L. Khalymbadzha Igor А. Rusinov Vladimir L. Paramonov Alexander S. Arseniev Alexander S. Shenkarev Zakhar O. Charushin Valery N. Chupakhin Oleg N. 《Chemistry of Heterocyclic Compounds》2021,57(4):479-482
Chemistry of Heterocyclic Compounds - Isotope-labeled antiviral drug Triazavirin containing 2H, 13C, and 15N atoms in its structure has been synthesized. 13C2H3I and KS13CN served as donors of 13C... 相似文献
60.
Oleg G. Sinyashin Irina P. Romanova Gulshat G. Yusupova Valery I. Kovalenko Yuri Y. Efremov Irina I. Vandyukova 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract Data on the structure of cycloadducts of organophosphorus dipolar reagents and fullerenes arc absent, to our knowledge. We died the reactions and the shucturc of cycloadducts of phosphorylated azidcs and nitrile oxide with [60]fullcrcnc. The cycloaddition of diphcnylphosphinic llzide to fullcrme has bcm determined to lead to the 1 -[(N-diphenylphosphoryl)amino]-2-hydroxy[6O]hllcrme (l), the mixhuc of phosphorylated aziridinofullcrcne (2) and derivative of fullerne (3) with one aziridine fragment and one aminohydmxy-fragment, or to product (4), depending on the conditions of don . 相似文献