全文获取类型
收费全文 | 126篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
化学 | 103篇 |
晶体学 | 2篇 |
力学 | 1篇 |
数学 | 17篇 |
物理学 | 13篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 8篇 |
2012年 | 19篇 |
2011年 | 5篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1986年 | 1篇 |
1981年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
排序方式: 共有136条查询结果,搜索用时 244 毫秒
131.
Juliane Steingroewer Thomas Bley Christian Bergemann Elke Boschke 《Journal of magnetism and magnetic materials》2007
Analyses of food-borne pathogens are of great importance in order to minimize the health risk for customers. Thus, very sensitive and rapid detection methods are required. Current conventional culture techniques are very time consuming. Modern immunoassays and biochemical analysis also require pre-enrichment steps resulting in a turnaround time of at least 24 h. Biomagnetic separation (BMS) is a promising more rapid method. In this study we describe the isolation of high affine and specific peptides from a phage-peptide library, which combined with BMS allows the detection of Salmonella spp. with a similar sensitivity as that of immunomagnetic separation using antibodies. 相似文献
132.
Juliane Lehmann 《Proceedings of the American Mathematical Society》2008,136(11):3785-3793
We generalize the concept of combinatorial nested set complexes to posets and exhibit the topological relationship between the arising nested set complexes and the order complex of the underlying poset. In particular, a sufficient condition is given so that this relationship is actually a subdivision.
We use the results to generalize the proof method of Čukić and Delucchi, so far restricted to semilattices, for a result of Björner, Paffenholz, Sjöstrand and Ziegler on the Bier construction on posets.
133.
Juliane Maurer 《Archiv der Mathematik》1977,28(1):193-199
Ohne ZusammenfassungHerrn Professor W. v. Waldenfels danke ich herzlich für seine Unterstützung bei der Bearbeitung dieses Themas. 相似文献
134.
Schumacher HC Alves M Leite CA Santos JP Neto ET Murakami MM Galembeck F do Amaral M 《Journal of colloid and interface science》2007,305(2):256-263
Stable cationic latices were prepared by charge inversion of anionic styrene-acrylic copolymer latices upon binding Al3+ and Fe3+ ions. This is achieved by stabilizing the latices with a high-HLB (hydrophile-lypophile balance) nonionic surfactant that imparts strong steric stability to the latex, even in the presence of high concentrations of multivalent counterions while these are bound to the latex anionic sites. The cationic latices thus prepared have good stability properties, and the same procedure should be applicable to essentially any latex-carrying anionic sites. Analytical ESI-TEM images show that particle-bound iron is concentrated at the particle borders, but it is also found in the particle bulk. 相似文献
135.
Letícia S. Contieri Leonardo M de Souza Mesquita Vitor L. Sanches Juliane Viganó Renan Canute Kamikawachi Wagner Vilegas Mauricio A. Rostagno 《Journal of separation science》2023,46(3):2200440
Propolis is a bee product with a complex chemical composition formed by several species from different geographical origins. The complex propolis composition requires an accurate and reproducible characterization of samples to standardize the quality of the material sold to consumers. This work developed an ultra-high-performance liquid chromatography with a photodiode array detector method to analyze propolis phenolic compounds based on the two key propolis biomarkers, Artepillin C and p-Coumaric acid. This choice was made due to the complexity of the sample with the presence of several compounds. The optimized method was hyphenated with mass spectrometry detection allowing the detection of 23 different compounds. A step-by-step strategy was used to optimize temperature, flow rate, mobile phase composition, and re-equilibration time. Reverse-phase separation was achieved with a C18 fused-core column packed with the commercially available smallest particles (1.3 nm). Using a fused-core column with ultra-high-performance liquid chromatography allows highly efficient, sensitive, accurate, and reproducible determination of compounds extracted from propolis with an outstanding sample throughput and resolution. Optimized conditions permitted the separation of the compounds in 5.50 min with a total analysis time (sample-to-sample) of 6.50 min. 相似文献
136.
Dr. Daniel M. Wanner Patrick M. Becker Simon Suhr Dr. Nick Wannenmacher Dr. Slava Ziegler Justin Herrmann Dr. Felix Willig Julia Gabler Khushbu Jangid Dr. Juliane Schmid Andreas C. Hans Dr. Wolfgang Frey Prof. Dr. Biprajit Sarkar Prof. Dr. Johannes Kästner Prof. Dr. René Peters 《Angewandte Chemie (International ed. in English)》2023,62(36):e202307317
Pyrazolones represent an important structural motif in active pharmaceutical ingredients. Their asymmetric synthesis is thus widely studied. Still, a generally highly enantio- and diastereoselective 1,4-addition to nitroolefins providing products with adjacent stereocenters is elusive. In this article, a new polyfunctional CuII-1,2,3-triazolium-aryloxide catalyst is presented which enables this reaction type with high stereocontrol. DFT studies revealed that the triazolium stabilizes the transition state by hydrogen bonding between C(5)−H and the nitroolefin and verify a cooperative mode of activation. Moreover, they show that the catalyst adopts a rigid chiral cage/pore structure by intramolecular hydrogen bonding, by which stereocontrol is achieved. Control catalyst systems confirm the crucial role of the triazolium, aryloxide and CuII, requiring a sophisticated structural orchestration for high efficiency. The addition products were used to form pyrazolidinones by chemoselective C=N reduction. These heterocycles are shown to be valuable precursors toward β,γ’-diaminoamides by chemoselective nitro and N−N bond reductions. Morphological profiling using the Cell painting assay identified biological activities for the pyrazolidinones and suggest modulation of DNA synthesis as a potential mode of action. One product showed biological similarity to Camptothecin, a lead structure for cancer therapy. 相似文献