全文获取类型
收费全文 | 504篇 |
免费 | 8篇 |
国内免费 | 4篇 |
专业分类
化学 | 340篇 |
力学 | 15篇 |
数学 | 99篇 |
物理学 | 62篇 |
出版年
2021年 | 6篇 |
2019年 | 4篇 |
2016年 | 16篇 |
2015年 | 5篇 |
2014年 | 15篇 |
2013年 | 15篇 |
2012年 | 18篇 |
2011年 | 15篇 |
2010年 | 6篇 |
2009年 | 15篇 |
2008年 | 17篇 |
2007年 | 18篇 |
2006年 | 18篇 |
2005年 | 9篇 |
2004年 | 4篇 |
2003年 | 14篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1996年 | 5篇 |
1992年 | 5篇 |
1989年 | 3篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1984年 | 5篇 |
1982年 | 7篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1889年 | 4篇 |
1887年 | 7篇 |
1886年 | 5篇 |
1884年 | 12篇 |
1883年 | 11篇 |
1882年 | 16篇 |
1881年 | 12篇 |
1880年 | 16篇 |
1878年 | 5篇 |
1877年 | 6篇 |
1875年 | 7篇 |
1874年 | 5篇 |
1873年 | 4篇 |
1872年 | 16篇 |
1871年 | 12篇 |
1870年 | 18篇 |
1869年 | 5篇 |
1868年 | 4篇 |
1867年 | 8篇 |
1865年 | 7篇 |
1864年 | 8篇 |
排序方式: 共有516条查询结果,搜索用时 17 毫秒
91.
Tobias Rudolph Markus J. Barthel Florian Kretschmer Ulrich Mansfeld Stephanie Hoeppener Martin D. Hager Ulrich S. Schubert Felix H. Schacher 《Macromolecular rapid communications》2014,35(9):916-921
Furfuryl glycidyl ether (FGE) represents a highly versatile monomer for the preparation of reversibly cross‐linkable nanostructured materials via Diels–Alder reactions. Here, the use of FGE for the mid‐chain functionalization of a P2VP‐b‐PEO diblock copolymer is reported. The material features one furan moiety at the block junction, P2VP68‐FGE‐b‐PEO390, which can be subsequently addressed in Diels–Alder reactions using maleimide‐functionalized counterparts. The presence of the FGE moiety enables the introduction of dyes as model labels or the formation of hetero‐grafted brushes as shell on hybrid Au@Polymer nanoparticles. This renders P2VP68‐FGE‐b‐PEO390, a powerful tool for selective functionalization reactions, including the modification of surfaces.
92.
Florian Kretschmer Stefan Mühlig Stephanie Hoeppener Andreas Winter Martin D. Hager Carsten Rockstuhl Thomas Pertsch Ulrich S. Schubert 《Particle & Particle Systems Characterization》2014,31(7):721-744
The unique properties of plasmonic nanostructures have fuelled research based on the tremendous amount of potential applications. Their tailor‐made assemblies in combination with the tunable size and morphology of the initial building blocks allow for the creation of materials with a desired optical response. In this respect, it is crucial to synthesize nanoparticles with a defined shape that are at the core of such developments. Moreover, the interaction of individual nanoparticles with an incident electromagnetic field cannot only be influenced by their structure, but in fact, also by their spatial arrangement to each other. To harvest such opportunities, a profound theoretical understanding of these interactions is required as well as concise strategies to create such ordered assemblies. A quantitative evaluation of their optical properties can only be conducted when discrete structures of high uniformity can be achieved. As a consequence, separation steps have to be applied in order to obtain materials of high purity and uniformity. This also allows for an easier structural characterization of the nanoparticles and their assembled superstructures. In this progress report, an overview about the current development in this field of research is provided. 相似文献
93.
94.
The energy input and frequency shift of geodesic acoustic modes (GAMs) due to turbulence in tokamak edge plasmas are investigated in numerical two-fluid turbulence studies. Surprisingly, the turbulent GAM dispersion relation is qualitatively equivalent to the linear GAM dispersion but can have drastically enhanced group velocities. In up-down asymmetric geometry the energy input due to turbulent transport may favor the excitation of GAMs with one particular sign of the radial phase velocity relative to the magnetic drifts and may lead to pulsed GAM activity. 相似文献
95.
Wild A Winter A Hager MD Schubert US 《Chemical communications (Cambridge, England)》2012,48(7):964-966
Water-based Zn(II) bisterpyridine systems were used as fluorometric sensors for the detection of the nerve gas G mimics DMMP, DCP and DCNP. Analyte concentrations in the range of 10(-7) to 10(-6) M are detectable in solution. The utilization of a test stripe additionally allows the detection of organophosphonates from the gas phase. 相似文献
96.
Alexander M. Breul Christian Pietsch Roberto Menzel Johann Schäfer Anke Teichler Martin D. Hager Jürgen Popp Benjamin Dietzek Rainer Beckert Ulrich S. Schubert 《European Polymer Journal》2012,48(7):1339-1347
Blue emitting dyes bearing a luciferin analogous chromophore were attached to a polystyrene backbone. For this purpose, 4-hydroxy-1,3-thiazoles were functionalized with a styrene unit and polymerized using the reversible addition–fragmentation chain transfer (RAFT) polymerization technique. Two different chain transfer agents were investigated and one monomer was studied in terms of its kinetic behavior. The polymerization kinetics are presented and discussed in detail, showing a controlled polymerization behavior, resulting in well-defined copolymers with polydispersity indices below 1.2. The obtained polymers were characterized by size exclusion chromatography (SEC), 1H NMR, MALDI-TOF MS and UV–vis absorption and fluorescence spectroscopy. In addition, the UV–vis absorption and emission behavior was investigated in thin films. 相似文献
97.
In this paper, we develop the mass and energy jump conditions for a vapor–liquid boundary within a porous medium. The analysis is restricted to a single fluid component and leads to the appropriate jump conditions for an evaporation front. The condition of local thermal equilibrium is assumed to exist in the homogeneous liquid and vapor regions, but not in the boundary region where rapid changes in the saturation occur. 相似文献
98.
N. G. Basov G. D. Hager A. A. Ionin A. A. Kotkov A. K. Kurnosov J. E. McCord A. P. Napartovich L. V. Seleznev N. G. Turkin 《Optics Communications》2000,180(4-6):285-300
Tunable single-line first-overtone (FO) CO lasing on wavelengths from 2.7 up to 4.2 μm corresponding to overtone vibrational transitions from 13→11 up to 38→36 on 413 ro-vibrational lines was experimentally obtained. A parametric study of energetic and spectral characteristics of the single-line FO CO laser was carried out. Energy distribution over ro-vibrational lines was measured. The maximum specific output energy (SOE) came up to 3 J/l Amagat, with single-line output efficiency being up to 0.6%. For the first time, a multi-quantum theoretical model was used to describe the tunable single-line FO CO laser. This multi-quantum approach demonstrated better agreement between theoretical calculations and observed experimental data for laser output as a function of vibrational quantum numbers. 相似文献
99.
Asmaa H. Mohamed Hager S. Abdelmeged Raafat M. Shaker Fathy F. Abdel-Latif 《Journal of heterocyclic chemistry》2021,58(12):2372-2380
The present article describes a facile one-pot synthesis of a new series of 4,4′-(1,4-phenylene)-dipyrimidines ( 6a–c and 10a, b ) by the reaction of terephthalaldehyde ( 1 ), 2-acetylthiophene, and/or nitriles with S-benzylthiouronium chloride 3a . And also, the di-pyrimidinones 13a-d were obtained by the reaction of different amidines 3a–d and ethyl cyanoacetate ( 11 ) with terephthalaldehyde ( 1 ) under solvent-free conditions in the existence of sodium hydroxide which is found to be a more efficient base for these reactions. The final products were characterized by spectral data and elemental analysis, IR, MS, 1 H, and 13 C NMR spectroscopy. 相似文献
100.
H. Hager 《Fresenius' Journal of Analytical Chemistry》1879,18(1):615-617
Ohne Zusammenfassung 相似文献