全文获取类型
收费全文 | 2620篇 |
免费 | 81篇 |
国内免费 | 29篇 |
专业分类
化学 | 1662篇 |
晶体学 | 13篇 |
力学 | 57篇 |
数学 | 555篇 |
物理学 | 443篇 |
出版年
2023年 | 10篇 |
2022年 | 39篇 |
2021年 | 101篇 |
2020年 | 43篇 |
2019年 | 56篇 |
2018年 | 55篇 |
2017年 | 48篇 |
2016年 | 98篇 |
2015年 | 75篇 |
2014年 | 111篇 |
2013年 | 190篇 |
2012年 | 181篇 |
2011年 | 187篇 |
2010年 | 127篇 |
2009年 | 123篇 |
2008年 | 147篇 |
2007年 | 161篇 |
2006年 | 148篇 |
2005年 | 155篇 |
2004年 | 121篇 |
2003年 | 84篇 |
2002年 | 60篇 |
2001年 | 25篇 |
2000年 | 26篇 |
1999年 | 30篇 |
1998年 | 23篇 |
1997年 | 29篇 |
1996年 | 24篇 |
1995年 | 30篇 |
1994年 | 22篇 |
1993年 | 22篇 |
1992年 | 14篇 |
1991年 | 18篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 23篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1969年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有2730条查询结果,搜索用时 31 毫秒
991.
Influence of the Homopolar Dihydrogen Bonding CH⋅⋅⋅HC on Coordination Geometry: Experimental and Theoretical Studies
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)
Dr. Damir A. Safin Dr. Maria G. Babashkina Dr. Koen Robeyns Dr. Mariusz P. Mitoraj Dr. Piotr Kubisiak Prof. Yann Garcia 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(46):16679-16687
The reaction of the N‐thiophosphorylated thiourea (HOCH2)(Me)2CNHC(S)NHP(S)(OiPr)2 (HL), deprotonated by the thiophosphorylamide group, with NiCl2 leads to green needles of the pseudotetrahedral complex [Ni(L‐1,5‐S,S′)2] ? 0.5 (n‐C6H14) or pale green blocks of the trans square‐planar complex trans‐[Ni(L‐1,5‐S,S′)2]. The former complex is stabilized by homopolar dihydrogen C?H???H?C interactions formed by n‐hexane solvent molecules with the [Ni(L‐1,5‐S,S′)2] unit. Furthermore, the dispersion‐dominated C?H??? H?C interactions are, together with other noncovalent interactions (C?H???N, C?H???Ni, C?H???S), responsible for pseudotetrahedral coordination around the NiII center in [Ni(L ‐1,5‐S,S′)2] ? 0.5 (n‐C6H14). 相似文献
992.
L-selectin is a protein with potential importance for numerous diseases and clinical disorders. In this paper, we present a new aptamer-based luminescent assay developed to detect L-selectin. The sensing system working principle is based on Förster Resonance Energy Transfer (FRET) from a donor terbium complex (TbC) to an acceptor cyanine dye (Cy5). In the present approach, the biotinylated aptamer is combined with Cy5-labelled streptavidin (Cy5-Strep) to yield an aptamer-based acceptor construct (Apta-Cy5-Strep), while L-selectin is conjugated using luminescent TbC. Upon aptamer binding to the TbC-labelled L-selectin (L-selectin-TbC), permanent donor-acceptor proximity is established which allows for radiationless energy transfer to occur. However, when unlabelled L-selectin is added, it competes with the L-selectin-TbC and the FRET signal decreases as the L-selectin concentration increases. FRET from the TbC to Cy5 was observed with time-gated time-resolved luminescence spectroscopy. A significant change in the corrected luminescence signal was observed in the dynamic range of 10–500 ng/mL L-selectin, the concentration range relevant for accelerated cognitive decline of Alzheimer's disease, with a limit of detection (LOD) equal to 10 ng/mL. The aptasensor-based assay is homogeneous and can be realized within one hour. Therefore, this method has the potential to become an alternative to tedious heterogeneous analytical methods, e.g. based on enzyme-linked immunosorbent assay (ELISA). 相似文献
993.
994.
An Allosteric Receptor by Simultaneous “Casting” and “Molding” in a Dynamic Combinatorial Library
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Jianwei Li Piotr Nowak Prof. Dr. Sijbren Otto 《Angewandte Chemie (International ed. in English)》2015,54(3):833-837
Allosteric synthetic receptors are difficult to access by design. Herein we report a dynamic combinatorial strategy towards such systems based on the simultaneous use of two different templates. Through a process of simultaneous casting (the assembly of a library member around a template) and molding (the assembly of a library member inside the binding pocket of a template), a Russian‐doll‐like termolecular complex was obtained with remarkable selectivity. Analysis of the stepwise formation of the complex indicates that binding of the two partners by the central macrocycle exhibits significant positive cooperativity. Such allosteric systems represent hubs that may have considerable potential in systems chemistry. 相似文献
995.
Localized Template‐Driven Functionalization of Nanoparticles by Dynamic Combinatorial Chemistry
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Piotr Nowak Dr. Vittorio Saggiomo Dr. Fatemeh Salehian Mathieu Colomb‐Delsuc Dr. Yang Han Prof. Dr. Sijbren Otto 《Angewandte Chemie (International ed. in English)》2015,54(14):4192-4197
We have developed a method for the localized functionalization of gold nanoparticles using imine‐based dynamic combinatorial chemistry. By using DNA templates, amines were grafted on the aldehyde‐functionalized nanoparticles only if and where the nanoparticles interacted with the template molecules. Functionalization of the nanoparticles was controlled solely by the DNA template; only amines capable of interacting with DNA were bound to the surface. Interestingly, even though our libraries contained only a handful of simple amines, the DNA sequence influenced their attachment to the surface. Our method opens up new opportunities for the synthesis of multivalent, nanoparticle‐based receptors for biomacromolecules. 相似文献
996.
Dr. Qing Li Prof. Xiaodong Wen Prof. Gang Wu Dr. Hoon T. Chung Dr. Rui Gao Dr. Piotr Zelenay 《Angewandte Chemie (International ed. in English)》2015,54(26):7524-7528
Dimethyl ether (DME) has been considered as a promising alternative fuel for direct‐feed fuel cells but lack of an efficient DME oxidation electrocatalyst has remained the challenge for the commercialization of the direct DME fuel cell. The commonly studied binary PtRu catalyst shows much lower activity in DME than methanol oxidation. In this work, guided by density functional theory (DFT) calculation, a ternary carbon‐supported PtRuPd catalyst was designed and synthesized for DME electrooxidation. DFT calculations indicated that Pd in the ternary PtRuPd catalyst is capable of significantly decreasing the activation energy of the C? O and C? H bond scission during the oxidation process. As evidenced by both electrochemical measurements in an aqueous electrolyte and polymer‐electrolyte fuel cell testing, the ternary catalyst shows much higher activity (two‐fold enhancement at 0.5 V in fuel cells) than the state‐of‐the‐art binary Pt50Ru50/C catalyst (HiSPEC 12100). 相似文献
997.
Dr. Dmitrij Rappoport Tomasz Żaba Dr. Mathieu Gonidec Prof. Dr. Piotr Cyganik Prof. Dr. Alan Aspuru‐Guzik Prof. Dr. George M. Whitesides 《Angewandte Chemie (International ed. in English)》2015,54(49):14743-14747
This work examines charge transport (CT) through self‐assembled monolayers (SAMs) of oligoglycines having an N‐terminal cysteine group that anchors the molecule to a gold substrate, and demonstrate that CT is rapid (relative to SAMs of n‐alkanethiolates). Comparisons of rates of charge transport‐using junctions with the structure AuTS/SAM//Ga2O3/EGaIn (across these SAMs of oligoglycines, and across SAMs of a number of structurally and electronically related molecules) established that rates of charge tunneling along SAMs of oligoglycines are comparable to that along SAMs of oligophenyl groups (of comparable length). The mechanism of tunneling in oligoglycines is compatible with superexchange, and involves interactions among high‐energy occupied orbitals in multiple, consecutive amide bonds, which may by separated by one to three methylene groups. This mechanistic conclusion is supported by density functional theory (DFT). 相似文献
998.
999.
Piotr Pacholak Dr. Krzysztof Gontarczyk Dr. Radosław Kamiński Dr. Krzysztof Durka Prof. Sergiusz Luliński 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(56):12758-12768
Two covalent organic frameworks comprising Lewis basic PIII centers and Lewis acidic boron atoms were prepared by poly-condensation reactions of newly obtained tris(4-diisopropoxyborylphenyl)phosphine with 2,3,6,7,10,11-hexahydroxytriphenylene and 2,3,6,7-tetrahydroxy-9,10-dimethylanthracene. Obtained materials exhibit significant sorption of dihydrogen (100 cm3 g−1 at 1 bar at 77 K), methane (20 cm3 g−1 at 1 bar at 273 K) and carbon dioxide (50 cm3 g−1 at 1 bar at 273 K). They were exploited as solid-state ligands for coordination of Pd0 centers. Alternatively, in a bottom-up approach, boronated phosphine was treated with Pd2dba3 and poly-condensated, yielding hybrid materials where the polymer networks are formed by means of covalent boronate linkages and coordination P−Pd bonds. In addition, the analogous materials based on phosphine oxide were synthesized. The DFT calculations on framework–guest interactions revealed that the behavior of adjacent boron and phosphorus/phosphine oxide centers is reminiscent of that found in Frustrated Lewis Pairs and may improve sorption of selected molecules. 相似文献
1000.
Dr. Zhenyou Li Dr. Bhaghavathi P. Vinayan Dr. Piotr Jankowski Dr. Christian Njel Ananyo Roy Prof. Tejs Vegge Dr. Julia Maibach Prof. Juan Maria García Lastra Prof. Maximilian Fichtner Dr. Zhirong Zhao-Karger 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(28):11580-11587
The development of multivalent metal (such as Mg and Ca) based battery systems is hindered by lack of suitable cathode chemistry that shows reversible multi-electron redox reactions. Cationic redox centres in the classical cathodes can only afford stepwise single-electron transfer, which are not ideal for multivalent-ion storage. The charge imbalance during multivalent ion insertion might lead to an additional kinetic barrier for ion mobility. Therefore, multivalent battery cathodes only exhibit slope-like voltage profiles with insertion/extraction redox of less than one electron. Taking VS4 as a model material, reversible two-electron redox with cationic–anionic contributions is verified in both rechargeable Mg batteries (RMBs) and rechargeable Ca batteries (RCBs). The corresponding cells exhibit high capacities of >300 mAh g−1 at a current density of 100 mA g−1 in both RMBs and RCBs, resulting in a high energy density of >300 Wh kg−1 for RMBs and >500 Wh kg−1 for RCBs. Mechanistic studies reveal a unique redox activity mainly at anionic sulfides moieties and fast Mg2+ ion diffusion kinetics enabled by the soft structure and flexible electron configuration of VS4. 相似文献