全文获取类型
收费全文 | 251064篇 |
免费 | 2543篇 |
国内免费 | 454篇 |
专业分类
化学 | 135373篇 |
晶体学 | 3712篇 |
力学 | 11818篇 |
综合类 | 14篇 |
数学 | 29193篇 |
物理学 | 73951篇 |
出版年
2021年 | 2692篇 |
2020年 | 2955篇 |
2019年 | 3458篇 |
2018年 | 4617篇 |
2017年 | 4442篇 |
2016年 | 6307篇 |
2015年 | 3675篇 |
2014年 | 5631篇 |
2013年 | 11355篇 |
2012年 | 10059篇 |
2011年 | 11369篇 |
2010年 | 8413篇 |
2009年 | 8234篇 |
2008年 | 10464篇 |
2007年 | 10428篇 |
2006年 | 9190篇 |
2005年 | 8342篇 |
2004年 | 7715篇 |
2003年 | 6851篇 |
2002年 | 6637篇 |
2001年 | 6448篇 |
2000年 | 4854篇 |
1999年 | 3635篇 |
1998年 | 3081篇 |
1997年 | 3093篇 |
1996年 | 2978篇 |
1995年 | 2495篇 |
1994年 | 2665篇 |
1993年 | 2560篇 |
1992年 | 2880篇 |
1991年 | 2951篇 |
1990年 | 2848篇 |
1989年 | 2905篇 |
1988年 | 2759篇 |
1987年 | 2773篇 |
1986年 | 2610篇 |
1985年 | 3395篇 |
1984年 | 3439篇 |
1983年 | 2816篇 |
1982年 | 2863篇 |
1981年 | 2819篇 |
1980年 | 2590篇 |
1979年 | 2959篇 |
1978年 | 2910篇 |
1977年 | 3062篇 |
1976年 | 3114篇 |
1975年 | 2876篇 |
1974年 | 2827篇 |
1973年 | 2925篇 |
1972年 | 2175篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
A. K. Gatin M. V. Grishin S. A. Gurevich N. V. Dokhlikova A. A. Kirsankin V. M. Kozhevin E. S. Lokteva T. N. Rostovshchikova S. Yu. Sarvadii B. R. Shub D. A. Yavsin 《Russian Chemical Bulletin》2015,64(10):2337-2343
Nickel nanoparticles were deposited on the surface of highly oriented pyrolytical graphite by laser electrodispersion and precipitation from a solution of reverse micelles. The particles were studied using scanning tunneling microscopy and spectroscopy as well as Auger spectroscopy. The elemental composition of the nanoparticles and specific features of the electronic structure of their surface were determined. Adsorption of molecular hydrogen was also studied. 相似文献
32.
33.
34.
A. A. Popovich P. A. Novikov A. O. Silin N. G. Razumov M. Yu. Maximov Wang Quing Sheng 《Russian Journal of Applied Chemistry》2015,88(10):1633-1636
A study of the Li2FeSiO4/C cathode material doped with Mn demonstrated that introduction of polymethyl methacrylate results in a substantial decrease in the particle size and increase in the specific surface area of the cathode material. Polymethyl methacrylate strongly improves the cyclic stability of the cathode material. The discharge capacity after the first cycle was 218 mA h g–1, and that upon stabilization of the structure of the cathode material, 170 mA h g–1. 相似文献
35.
Structural Characterization of O‐ and C‐Glycosylating Variants of the Landomycin Glycosyltransferase LanGT2 下载免费PDF全文
Dr. Heng Keat Tam Dr. Johannes Härle Dr. Stefan Gerhardt Prof. Dr. Jürgen Rohr Guojun Wang Prof. Dr. Jon S. Thorson Dr. Aurélien Bigot Monika Lutterbeck Dr. Wolfgang Seiche Prof. Dr. Bernhard Breit Prof. Dr. Andreas Bechthold Prof. Dr. Oliver Einsle 《Angewandte Chemie (International ed. in English)》2015,54(9):2811-2815
The structures of the O‐glycosyltransferase LanGT2 and the engineered, C? C bond‐forming variant LanGT2S8Ac show how the replacement of a single loop can change the functionality of the enzyme. Crystal structures of the enzymes in complex with a nonhydrolyzable nucleotide‐sugar analogue revealed that there is a conformational transition to create the binding sites for the aglycon substrate. This induced‐fit transition was explored by molecular docking experiments with various aglycon substrates. 相似文献
36.
Dominika Topol’ská Katarína Valachová Peter Rapta Stanislav Šilhár Elena Panghyová Anton Horváth Ladislav Šoltés 《Chemical Papers》2015,69(9):1202-1210
Potential protective effects of elderberry (Sambucus nigra) extracts against oxidative degradation of hyaluronan (HA) were detected in vitro. To induce free-radical-mediated HA degradation, Weissberger’s biogenic oxidative system, which mimics the situation of acute inflammation, was applied. Time- and dose-dependent changes of dynamic viscosity of the HA solutions in the presence and absence of two elderberry extracts produced in 2006 and 2012 were recorded by rotational viscometry (RV). Radical scavenging capacity of both extracts was investigated by the spectrocolorimetric ABTS [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] assay and the “inverted” ABTS assay. Oxygen consumption of the system oxidizing HA either in the absence or presence of the elderberry extracts was determined. The results of RV revealed that an addition of the newer extract (2012) promoted the inhibition of HA degradation more markedly compared to the older extract (2006). The same effect of both extracts on ABTS·+ scavenging was observed. Inverted ABTS assay demonstrated that colorful substances were not responsible for the radical-scavenging activity. Results of oximetry demonstrated that the effect of the extract from 2006 was more significant than that of the extract from 2012. 相似文献
37.
Kaur Jagjeet Dubey Vikas Parganiha Yogita Singh Deepti Suryanarayana N. S. 《Research on Chemical Intermediates》2015,41(6):3597-3621
Research on Chemical Intermediates - In this paper we review the luminescence properties of Pr3+-doped CaTiO3 phosphors, the different methods of sample preparation, and characterization of the... 相似文献
38.
MgI2‐Mediated Chemoselective Cleavage of Protecting Groups: An Alternative to Conventional Deprotection Methodologies 下载免费PDF全文
Mathéo Berthet Florian Davanier Dr. Gilles Dujardin Prof. Jean Martinez Dr. Isabelle Parrot 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11014-11016
The scope of MgI2 as a valuable tool for quantitative and mild chemoselective cleavage of protecting groups is described here. This novel synthetic approach expands the use of protecting groups, widens the concept of orthogonality in synthetic processes, and offers a facile opportunity to release compounds from solid supports. 相似文献
39.
Frontispiece: Combined Spectroscopic and Electrochemical Detection of a NiI⋅⋅⋅HN Bonding Interaction with Relevance to Electrocatalytic H2 Production 下载免费PDF全文
40.