全文获取类型
收费全文 | 21878篇 |
免费 | 2373篇 |
国内免费 | 1429篇 |
专业分类
化学 | 15465篇 |
晶体学 | 250篇 |
力学 | 898篇 |
综合类 | 100篇 |
数学 | 2351篇 |
物理学 | 6616篇 |
出版年
2023年 | 315篇 |
2022年 | 453篇 |
2021年 | 558篇 |
2020年 | 658篇 |
2019年 | 652篇 |
2018年 | 499篇 |
2017年 | 483篇 |
2016年 | 837篇 |
2015年 | 787篇 |
2014年 | 924篇 |
2013年 | 1376篇 |
2012年 | 1742篇 |
2011年 | 1919篇 |
2010年 | 1185篇 |
2009年 | 1201篇 |
2008年 | 1402篇 |
2007年 | 1334篇 |
2006年 | 1167篇 |
2005年 | 1035篇 |
2004年 | 862篇 |
2003年 | 678篇 |
2002年 | 655篇 |
2001年 | 532篇 |
2000年 | 460篇 |
1999年 | 379篇 |
1998年 | 311篇 |
1997年 | 257篇 |
1996年 | 292篇 |
1995年 | 268篇 |
1994年 | 268篇 |
1993年 | 222篇 |
1992年 | 198篇 |
1991年 | 169篇 |
1990年 | 178篇 |
1989年 | 117篇 |
1988年 | 136篇 |
1987年 | 100篇 |
1986年 | 105篇 |
1985年 | 130篇 |
1984年 | 94篇 |
1983年 | 78篇 |
1982年 | 69篇 |
1981年 | 62篇 |
1980年 | 57篇 |
1979年 | 43篇 |
1978年 | 45篇 |
1977年 | 45篇 |
1976年 | 45篇 |
1974年 | 55篇 |
1973年 | 47篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
991.
Influence of Intermolecular Interactions on Valence Tautomeric Behaviors in Two Polymorphic Dinuclear Cobalt Complexes
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)
Guo‐Ling Li Dr. Shinji Kanegawa Dr. Zi‐Shuo Yao Dr. Sheng‐Qun Su Shu‐Qi Wu Dr. You‐Gui Huang Dr. Soonchul Kang Prof. Dr. Osamu Sato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17130-17135
Two polymorphic structures have been well determined in a valence tautomeric (VT) dinuclear cobalt complex. These polymorphs showed distinct thermal‐ and photomagnetic behavior, and are thus ideal for studying the “pure” intermolecular factors to VT transitions. In polymorph 1A , the VT cations are arranged head‐to‐waist with their neighbors and exhibit weak π???π interactions, resulting in a gradual and incomplete thermal VT transition. In contrast, the cations in polymorph 1B are arranged head‐to‐tail and exhibit relatively strong π???π interactions, leading to an abrupt and complete thermal VT transition with adjustable hysteresis loop at around room temperature. The VT process for both polymorphs can be induced by light, but the light‐excited state of 1B? 2H2O has a higher thermal relaxation temperature than that of 1A? 3H2O. 相似文献
992.
993.
994.
995.
Inside Back Cover: Stepwise Assembly of MII7 Clusters Revealed by Mass Spectrometry,EXAFS, and Crystallography (Chem. Eur. J. 51/2016)
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)
996.
997.
SU CaiHong 《中国科学:物理学 力学 天文学(英文版)》2014,57(5):950-962
Up to now,the most widely used method for transition prediction is the one based on linear stability theory.When it is applied to three-dimensional boundary layers,one has to choose the direction,or path,along which the growth rate of the disturbance is to be integrated.The direction given by using saddle point method in the theory of complex variable function is seen as mathematically most reasonable.However,unlike the saddle point method applied to water waves,here its physical meaning is not so obvious,as the frequency and wave number may be complex.And on some occasions,in advancing the integration of the growth rate of the disturbance,up to a certain location,one may not be able to continue the integration,because the condition for specifying the direction set by the saddle point method can no longer be satisfied on the basis of continuously varying wave number.In this paper,these two problems are discussed,and suggestions for how to do transition prediction under the latter condition are provided. 相似文献
998.
Chang Ling Zhao Zhong Jian Chen Xue Song Bai Can Ding Ting Ju Long Fu Gang Wei Kang Ru Miao 《Molecular diversity》2014,18(3):687-700
This paper summarizes the main achievements about the structure–activity relationships of anthocyanidin glycosylation. Anthocyanidin glycosylation is the essential step of anthocyanin biosynthesis and also the prerequisite of the further modifications of anthocyanins, which is jointly characterized by the glycosylation site, the type and number of the glycosyl as well as the glycosidic bond type. It generally enhances the stability, results in the hypsochromic effect and blueing, decreases the bioavailability and anticancer activity, and decreases, increases, or does not change the antioxidant activity of the anthocyanidins or anthocyanins, which is synergetically determined by the glycosylation site and the type and number of the glycosyl. Thereinto, in nature, the blue hues caused by the glycosylation may also be reinforced by the formation of the anthocyanic vacuolar inclusions. This review could provide a reference for the research of the structure-optimizing and function-exploiting of anthocyanins. 相似文献
999.
1000.
Nonlinear Dynamics - A novel type of linear multi-step formulas is proposed for solving initial value problems, such as the problems of multi-body systems and vibration systems and a variety of... 相似文献