全文获取类型
收费全文 | 399篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
化学 | 207篇 |
晶体学 | 5篇 |
力学 | 2篇 |
数学 | 31篇 |
物理学 | 161篇 |
出版年
2021年 | 4篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 11篇 |
2012年 | 12篇 |
2011年 | 20篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 17篇 |
2007年 | 24篇 |
2006年 | 12篇 |
2005年 | 19篇 |
2004年 | 23篇 |
2003年 | 9篇 |
2002年 | 18篇 |
2001年 | 20篇 |
2000年 | 8篇 |
1999年 | 15篇 |
1998年 | 10篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 5篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1976年 | 3篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1971年 | 2篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1968年 | 6篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1935年 | 3篇 |
1934年 | 5篇 |
1933年 | 2篇 |
排序方式: 共有406条查询结果,搜索用时 31 毫秒
401.
Bernard A. Boukamp Nicolas Hildenbrand Pieter Nammensma Dave H.A. Blank 《Solid State Ionics》2011,192(1):404-408
The impedance is derived for a dense layer electrode of a mixed conducting oxide, assuming that the electronic resistance may be ignored. The influence of layer thickness, oxygen diffusion and surface exchange rate on the ‘General Finite Length Diffusion’ expression is evaluated. The thickness dependence is tested for a series of thin, dense layer electrodes of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) deposited on a Ce0.9Gd0.1O1.95 electrolyte by pulsed laser deposition (PLD). A minimum thickness is required to avoid the influence of contact points of the contacting Pt-gauze and sheet resistance, which is about 1 μm for the studied LSCF electrodes. LEISS surface analysis indicates that PLD deposition process easily leads to a significant Cr contamination of the LSCF surface. Electrochemical impedance spectroscopy analysis indicates that the influence on the exchange rate of this Cr-contamination is still negligible. 相似文献
402.
High-throughput mass finger printing and Lewis blood group assignment of human milk oligosaccharides
Blank D Gebhardt S Maass K Lochnit G Dotz V Blank J Geyer R Kunz C 《Analytical and bioanalytical chemistry》2011,401(8):2495-2510
The structural diversity of human milk oligosaccharides (HMOs) strongly depends on the Lewis (Le) blood group status of the
donor which allows a classification of these glycans into three different groups. Starting from 50 μL of human milk, a new
high-throughput, standardized, and widely automated mass spectrometric approach has been established which can be used for
correlation of HMO structures with the respective Lewis blood groups on the basis of mass profiles of the entire mixture of
glycans together with selected fragment ion spectra. For this purpose, the relative abundance of diagnostically relevant compositional
species, such as Hex2Fuc2 and Hex3HexNAc1Fuc2, as well as the relative intensities of characteristic fragment ions obtained thereof are of key importance. For each Lewis
blood group, i.e., Le(a − b+), Le(a + b−), and Le(a − b−), specific mass profile and fragment ion patterns could be thus verified.
The described statistically proven classification of the derived glycan patterns may be a valuable tool for analysis and comparison
of large sets of milk samples in metabolic studies. Furthermore, the outlined protocol may be used for rapid screening in
clinical studies and quality control of milk samples donated to milk banks. 相似文献
403.
Yildirim O Yilmaz MD Reinhoudt DN Blank DH Rijnders G Huskens J 《Langmuir : the ACS journal of surfaces and colloids》2011,27(16):9890-9894
Alkylphosphate self-assembled monolayers (SAMs) were prepared on Nb-doped SrTiO(3) (Nb-STO) conducting metal oxide substrates. Unlike thiols on gold, the alkylphosphate SAMs on Nb-STO exhibited an electrochemical stability over a wide voltage range from -2 to 2 V. Cyclic voltammetry showed that the SAM modification inhibited the electrochemical activity of the underlying conducting substrate with an efficiency dependent on the chain length. Impedance spectroscopy showed that SAM-modified Nb-STO substrates have a significantly higher resistance than bare substrates. 相似文献
404.
New metal-nanocarbon composites were obtained by high-energy (ball milling) pre-treatment of the powder mixture followed by high-pressure/high-temperature treatment. Acoustic microscopy was used to study elastic properties and bulk irregularities of the samples. 相似文献
405.
Anna-Maria Tsirigoni Melis Goktas Zeynep Atris Angelo Valleriani Ana Vila Verde Kerstin G. Blank 《Macromolecular bioscience》2023,23(5):2200563
Coiled coils (CCs) are key building blocks of biogenic materials and determine their mechanical response to large deformations. Of particular interest is the observation that CC-based materials display a force-induced transition from α-helices to mechanically stronger β-sheets (αβT). Steered molecular dynamics simulations predict that this αβT requires a minimum, pulling speed-dependent CC length. Here, de novo designed CCs with a length between four to seven heptads are utilized to probe if the transition found in natural CCs can be mimicked with synthetic sequences. Using single-molecule force spectroscopy and molecular dynamics simulations, these CCs are mechanically loaded in shear geometry and their rupture forces and structural responses to the applied load are determined. Simulations at the highest pulling speed (0.01 nm ns−1) show the appearance of β-sheet structures for the five- and six-heptad CCs and a concomitant increase in mechanical strength. The αβT is less probable at a lower pulling speed of 0.001 nm ns−1 and is not observed in force spectroscopy experiments. For CCs loaded in shear geometry, the formation of β-sheets competes with interchain sliding. β-sheet formation is only possible in higher-order CC assemblies or in tensile-loading geometries where chain sliding and dissociation are prohibited. 相似文献
406.