全文获取类型
收费全文 | 96772篇 |
免费 | 18869篇 |
国内免费 | 129篇 |
专业分类
化学 | 87206篇 |
晶体学 | 320篇 |
力学 | 3876篇 |
数学 | 11444篇 |
物理学 | 12924篇 |
出版年
2023年 | 4284篇 |
2022年 | 1667篇 |
2021年 | 2855篇 |
2020年 | 5043篇 |
2019年 | 2844篇 |
2018年 | 3267篇 |
2017年 | 1481篇 |
2016年 | 6860篇 |
2015年 | 6618篇 |
2014年 | 6104篇 |
2013年 | 8029篇 |
2012年 | 6701篇 |
2011年 | 4822篇 |
2010年 | 5497篇 |
2009年 | 4997篇 |
2008年 | 4294篇 |
2007年 | 4049篇 |
2006年 | 3060篇 |
2005年 | 2923篇 |
2004年 | 2530篇 |
2003年 | 2062篇 |
2002年 | 1764篇 |
2001年 | 1110篇 |
2000年 | 940篇 |
1999年 | 649篇 |
1998年 | 538篇 |
1997年 | 536篇 |
1996年 | 641篇 |
1995年 | 497篇 |
1994年 | 513篇 |
1993年 | 629篇 |
1992年 | 548篇 |
1991年 | 444篇 |
1985年 | 543篇 |
1984年 | 520篇 |
1982年 | 504篇 |
1981年 | 533篇 |
1980年 | 525篇 |
1979年 | 500篇 |
1978年 | 489篇 |
1977年 | 569篇 |
1976年 | 690篇 |
1975年 | 733篇 |
1974年 | 757篇 |
1973年 | 562篇 |
1972年 | 481篇 |
1971年 | 447篇 |
1970年 | 623篇 |
1969年 | 497篇 |
1968年 | 531篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
In this paper, we study the local linear convergence properties of a versatile class of Primal–Dual splitting methods for minimizing composite non-smooth convex optimization problems. Under the assumption that the non-smooth components of the problem are partly smooth relative to smooth manifolds, we present a unified local convergence analysis framework for these methods. More precisely, in our framework, we first show that (i) the sequences generated by Primal–Dual splitting methods identify a pair of primal and dual smooth manifolds in a finite number of iterations, and then (ii) enter a local linear convergence regime, which is characterized based on the structure of the underlying active smooth manifolds. We also show how our results for Primal–Dual splitting can be specialized to cover existing ones on Forward–Backward splitting and Douglas–Rachford splitting/ADMM (alternating direction methods of multipliers). Moreover, based on these obtained local convergence analysis result, several practical acceleration techniques are discussed. To exemplify the usefulness of the obtained result, we consider several concrete numerical experiments arising from fields including signal/image processing, inverse problems and machine learning. The demonstration not only verifies the local linear convergence behaviour of Primal–Dual splitting methods, but also the insights on how to accelerate them in practice. 相似文献
72.
Functional Binding Surface of a β‐Hairpin VEGF Receptor Targeting Peptide Determined by NMR Spectroscopy in Living Cells 下载免费PDF全文
Dr. Donatella Diana Anna Russomanno Dr. Lucia De Rosa Dr. Rossella Di Stasi Dr. Domenica Capasso Dr. Sonia Di Gaetano Dr. Alessandra Romanelli Dr. Luigi Russo Dr. Luca D. D'Andrea Prof. Roberto Fattorusso 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):91-95
In this study, the functional interaction of HPLW peptide with VEGFR2 (Vascular Endothelial Growth Factor Receptor 2) was determined by using fast 15N‐edited NMR spectroscopic experiments. To this aim, 15N uniformly labelled HPLW has been added to Porcine Aortic Endothelial Cells. The acquisition of isotope‐edited NMR spectroscopic experiments, including 15N relaxation measurements, allowed a precise characterization of the in‐cell HPLW epitope recognized by VEGFR2. 相似文献
73.
Inside Cover: Photoinduced Formation of an Azobenzene‐Based CD‐Active Supramolecular Cyclic Dimer (Chem. Eur. J. 18/2015) 下载免费PDF全文
74.
75.
76.
77.
Inside Cover: Ru‐Catalysed CH Arylation of Indoles and Pyrroles with Boronic Acids: Scope and Mechanistic Studies (Chem. Eur. J. 14/2015) 下载免费PDF全文
78.
Enantiomeric Cyclic Peptides with Different Caco‐2 Permeability Suggest Carrier‐Mediated Transport 下载免费PDF全文
B. Sc. Eduard Puig Prof. Dr. Beat Ernst Prof. Dr. Horst Kessler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8023-8027
Recently, oral absorption of cyclic hexapeptides was improved by N‐methylation of their backbone amides. However, the number and position of N‐methylations or of solvent exposed NHs did not correlate to intestinal permeability, measured in a Caco‐2 model. In this study, we investigate enantiomeric pairs of three polar and two lipophilic peptides to demonstrate the participation of carrier‐mediated transporters. As expected, all the enantiomeric peptides exhibited identical lipophilicity (logD7.4) and passive transcellular permeability determined by the parallel artificial membrane permeability assay (PAMPA). However, the enantiomeric polar peptides exhibited different Caco‐2 permeability (Papp) in both directions a–b and b–a. The same trend was observed for one of the lipophilic peptide, whereas the second lipophilic enantiomer pair showed identical Caco‐2 permeability (within the errors). These findings provide the first evidence for the involvement of carrier‐mediated transport for peptides, especially for those of polar nature. 相似文献
79.
Cover Picture: Coordination Chemistry of N‐Heterocyclic Nitrenium‐Based Ligands (Chem. Eur. J. 19/2015) 下载免费PDF全文
80.
Tuning the Basicity of Cyano‐Containing Ionic Liquids to Improve SO2 Capture through Cyano–Sulfur Interactions 下载免费PDF全文
Dr. Guokai Cui Fengtao Zhang Xiuyuan Zhou Prof. Haoran Li Prof. Jianji Wang Prof. Congmin Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5632-5639
A new approach has been developed to improve SO2 sorption by cyano‐containing ionic liquids (ILs) through tuning the basicity of ILs and cyano–sulfur interaction. Several kinds of cyano‐containing ILs with different basicity were designed, prepared, and used for SO2 capture. The interaction between these cyano‐containing ILs and SO2 was investigated by FTIR and NMR methods. Spectroscopic investigations and quantum chemical calculations showed that dramatic effects on SO2 capacity originate from the basicity of the ILs and enhanced cyano–sulfur interaction. Furthermore, the captured SO2 was easy to release by heating or bubbling N2 through the ILs. This efficient and reversible process, achieved by tuning the basicity of ILs, is an excellent alternative to current technologies for SO2 capture. 相似文献