全文获取类型
收费全文 | 3734篇 |
免费 | 427篇 |
国内免费 | 733篇 |
专业分类
化学 | 4620篇 |
晶体学 | 95篇 |
力学 | 2篇 |
综合类 | 10篇 |
数学 | 1篇 |
物理学 | 166篇 |
出版年
2024年 | 3篇 |
2023年 | 25篇 |
2022年 | 59篇 |
2021年 | 146篇 |
2020年 | 223篇 |
2019年 | 172篇 |
2018年 | 145篇 |
2017年 | 148篇 |
2016年 | 224篇 |
2015年 | 186篇 |
2014年 | 222篇 |
2013年 | 319篇 |
2012年 | 457篇 |
2011年 | 245篇 |
2010年 | 215篇 |
2009年 | 235篇 |
2008年 | 244篇 |
2007年 | 246篇 |
2006年 | 214篇 |
2005年 | 182篇 |
2004年 | 231篇 |
2003年 | 154篇 |
2002年 | 82篇 |
2001年 | 61篇 |
2000年 | 53篇 |
1999年 | 69篇 |
1998年 | 45篇 |
1997年 | 45篇 |
1996年 | 36篇 |
1995年 | 30篇 |
1994年 | 27篇 |
1993年 | 23篇 |
1992年 | 30篇 |
1991年 | 14篇 |
1990年 | 15篇 |
1989年 | 6篇 |
1988年 | 19篇 |
1987年 | 5篇 |
1986年 | 11篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
排序方式: 共有4894条查询结果,搜索用时 78 毫秒
991.
WA Nugent 《Angewandte Chemie (International ed. in English)》2012,51(36):8936-8949
When a research area "goes viral", the event typically occurs in conjunction with a major change in "conventional wisdom". In retrospect, the literature often contains earlier hints that the original judgment was not correct. These antecedents are referred to as "Black Swan" events. The picture shows research on homogeneous gold catalysis "going viral". 相似文献
992.
993.
994.
Ghitti M Spitaleri A Valentinis B Mari S Asperti C Traversari C Rizzardi GP Musco G 《Angewandte Chemie (International ed. in English)》2012,51(31):7702-7705
Ain't got that swing(-out): The cyclopeptide isoDGR is emerging as a new αvβ3 integrin binding motif. Agreement between the results of computational and biochemical studies reveals that isoDGR-containing cyclopeptides are true αvβ3 integrin antagonists that block αvβ3 in its inactive conformation (see scheme). isoDGR-based ligands may give αvβ3 antagonists without paradoxical effects. 相似文献
995.
将苯乙胺衍生的手性膦-亚磷酰胺酯配体应用在Rh-催化α-烯醇酯膦酸酯的不对称氢化反应中,考察了配体结构及反应条件对反应结果的影响,并在优化的条件下研究了各种底物的适用范围,产物的对映选择性最高>99%ee. 相似文献
996.
997.
Thermal Ammonia Activation by Cationic Transition‐Metal Hydrides of the First Row – Small but Mighty
The thermal reactions of cationic 3d transition‐metal hydrides MH+ (M=Sc–Zn, except V and Cu) with ammonia have been studied by gas‐phase experiments and computational methods. There are three primary reaction channels: 1) H2 elimination by N? H bond activation, 2) ligand exchange under the formation of M(NH3)+, and 3) proton transfer to yield NH4+. Computational studies of these three reaction channels have been performed for the couples MH+/NH3 (M=Sc–Zn) to elucidate mechanistic aspects and characteristic reaction patterns of the first row. For N? H activation, σ‐bond metathesis was found to be operative. 相似文献
998.
Caterina Fraschetti Matthias C. Letzel Marlene Paletta Jochen Mattay Maurizio Speranza Antonello Filippi Massimiliano Aschi Alexander B. Rozhenko 《Journal of mass spectrometry : JMS》2012,47(1):72-78
The effect of cyclochirality of rccc‐2,8,14,20‐tetra‐n‐decyl‐4,10,16,22‐tetra‐O‐methylresorcin[4]arene (C) on the enantiodiscrimination of a number of chiral bidentate and tridentate aromatic and aliphatic biomolecules (G) has been investigated by nano‐electrospray ionization (nano‐ESI)‐Fourier transform ion cyclotron resonance mass spectrometry. The experimental approach is based on the formation of diastereomeric proton‐bound [C·H·G]+ complexes by nano‐ESI of solutions containing an equimolar amount of quasi‐enantiomers (C) together with the chiral guest (G) and the subsequent measurement of the rate of the G substitution by the attack of several achiral and chiral amines. In general, the heterochiral complexes react faster than the homochiral ones, except when G is an aminoalcoholic neurotransmitter whose complexes, beyond that, exhibit the highest enantioselectivity. The kinetic results were further supported by both collision‐induced dissociation experiments on some of the relevant [C2·H·G]+ three‐body species and Density functional theory (DFT) calculations performed on the most selective systems. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
999.
Abstract Fluorescence correlation spectroscopy (FCS) is an important biophysical technique. FCS is currently being used in many areas of biology to solve several scientific problems. Its properties such as detection at the single molecular level, higher sensitivity, and use of lower sample volume make FCS a promising molecular diagnostic tool. The promising applications of FCS extend from DNA kinetics/dynamics studies to the comprehensive understanding of receptor–ligand interactions. In this article, we review various promising biological applications of FCS. 相似文献
1000.
Saroj Kumar 《应用光谱学评论》2013,48(3):187-200
AbstractThis brief review focuses on the information that can be obtained for biomolecules, especially proteins, by using the technique infrared-induced difference spectroscopy. 相似文献