全文获取类型
收费全文 | 303篇 |
免费 | 4篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 55篇 |
金属工艺 | 3篇 |
机械仪表 | 7篇 |
建筑科学 | 9篇 |
能源动力 | 3篇 |
轻工业 | 15篇 |
水利工程 | 2篇 |
无线电 | 29篇 |
一般工业技术 | 51篇 |
冶金工业 | 96篇 |
原子能技术 | 1篇 |
自动化技术 | 32篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 15篇 |
2012年 | 7篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 11篇 |
2008年 | 12篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 9篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 10篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 37篇 |
1997年 | 32篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1988年 | 4篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1979年 | 3篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1965年 | 1篇 |
1959年 | 2篇 |
1952年 | 1篇 |
1943年 | 1篇 |
1941年 | 1篇 |
1940年 | 4篇 |
排序方式: 共有307条查询结果,搜索用时 46 毫秒
241.
Dr. Katharina Streichert Dr. Carina Seitz Dr. Eugenia Hoffmann Dr. Irene Boos Prof. Wolfgang Jelkmann Prof. Thomas Brunner Prof. Carlo Unverzagt Dr. Marina Rubini 《Chembiochem : a European journal of chemical biology》2019,20(15):1914-1918
The biological activity of the glycoprotein hormone erythropoietin (EPO) is dependent mainly on the structure of its N-linked glycans. We aimed to readily attach defined N-glycans to EPO through copper-catalyzed azide alkyne cycloaddition. EPO variants with an alkyne-bearing non-natural amino acid (Plk) at the N-glycosylation sites 24, 38, and 83 were obtained by amber suppression followed by protein purification and refolding. Click conjugation of the alkynyl EPOs with biantennary N-glycan azides provided biologically active site-specifically modified EPO glycoconjugates. 相似文献
242.
Victor Bandlow Dr. Daniel Lauster Dr. Kai Ludwig Malte Hilsch Valentin Reiter-Scherer Prof. Dr. Jürgen P. Rabe Dr. Christoph Böttcher Prof. Dr. Andreas Herrmann Prof. Dr. Oliver Seitz 《Chembiochem : a European journal of chemical biology》2019,20(2):159-165
The surfaces of influenza A virus (IAV) particles are packed with hundreds of homo-trimeric hemagglutinins (HAs). Monovalent sugars have low affinity for HA, but distance-optimized bivalent sialyl-LacNAc (SLN) conjugates bind it with 103-fold enhanced potency. Herein, we describe the oligomerization of distance-optimized bivalent binders by branched and linear hybridization on long repetitive DNA templates. The most effective complexes fully inhibited IAVs at a DNA template concentration of 10−9 m . Although a 10−2 m concentration of free trisaccharide ligand is required for full inhibition of the virus, DNA templating enables a 104-fold reduction in the amount of sugar required. Notably, hybridization-induced rigidification of the DNA templates increased the serospecificity. Cryo-TEM analysis revealed that both spaghetti-type linear forms and cotton-ball-like clusters are able to bridge several adjacent HA molecules on the IAV surface. Programmed self-assembly of ligand–nucleic acid conjugates on long DNA templates might provide generic access to target-specific, high-affinity binders of proteins on globular objects such as cells and viruses. 相似文献
243.
Christian Scheibe Dr. Stefanie Wedepohl Sebastian B. Riese Dr. Jens Dernedde Prof. Dr. Oliver Seitz 《Chembiochem : a European journal of chemical biology》2013,14(2):236-250
Nucleic acid architectures offer intriguing opportunities for the interrogation of structural properties of protein receptors. In this study, we performed a DNA‐programmed spatial screening to characterize two functionally distinct receptor systems: 1) structurally well‐defined Ricinus communis agglutinin (RCA120), and 2) rather ill‐defined assemblies of L‐selectin on nanoparticles and leukocytes. A robust synthesis route that allowed the attachment both of carbohydrate ligands—such as N‐acetyllactosamine (LacNAc), sialyl‐Lewis‐X (sLeX), and mannose—and of a DNA aptamer to PNAs was developed. A systematically assembled series of different PNA–DNA complexes served as multivalent scaffolds to control the spatial alignments of appended lectin ligands. The spatial screening of the binding sites of RCA120 was in agreement with the crystal structure analysis. The study revealed that two appropriately presented LacNAc ligands suffice to provide unprecedented RCA120 affinity (KD=4 μM ). In addition, a potential secondary binding site was identified. Less dramatic binding enhancements were obtained when the more flexible L‐selectin assemblies were probed. This study involved the bivalent display both of the weak‐affinity sLeX ligand and of a high‐affinity DNA aptamer. Bivalent presentation led to rather modest (sixfold or less) enhancements of binding when the self‐assemblies were targeted against L‐selectin on gold nanoparticles. Spatial screening of L‐selectin on the surfaces of leukocytes showed higher affinity enhancements (25‐fold). This and the distance–activity relationships indicated that leukocytes permit dense clustering of L‐selectin. 相似文献
244.
Carolin Hampp Berit Ullmann Janin Reifenrath Nina Angrisani Dina Dziuba Dirk Bormann Jan‐Marten Seitz Andrea Meyer‐Lindenberg 《Advanced Engineering Materials》2012,14(3):B28-B37
Research on magnesium based degradable implant materials has finally obtained success in orthopaedics. Based on the previous good results with LAE442 magnesium alloy, the new LANd442 alloy was developed. In doing this, the single element neodymium replaces the rare earth compound. The primary objective of this study is to assess the biocompatibility of the new alloy in the rabbit model. During a 26 week period, the animals were investigated using clinical, radiological and in vivo µ‐CT techniques. Following euthanasia, histological, fluorescent microscopy and ex vivo µ‐CT investigations were done. Clinically, additional bone formed at the implant's location and accumulation of small amounts of subcutaneous gas can be observed. Radiological investigations show brightening of the medullary cavity and thickening in the region of the diaphysis. The µ‐computed tomographies reveal a reduction in the bone density from 1226.31 to 1192.95 mg HA/ccm together with increases in bone porosity from 4.55 to 6.6% and bone volume from 1.51 to 2.06 mm3 · slice?1. By means of fluorochrome sequential marking, the determined MARs lie between day 93 and 120 at 3.58 µm · d?1 and between day 120 and 179 at 2.25 µm · d?1. Elevated remodelling processes in the bone are histologically confirmed due to the periosteal and endosteal growths and an increased appearance of osteoclasts. Owing to the established considerable bone remodelling processes following intramedullary implantation, LANd442 appears to be a less suitable degradable implant material for cortical bone applications. 相似文献
245.
Carolin Hampp Nina Angrisani Janin Reifenrath Dirk Bormann Jan-Marten Seitz Andrea Meyer-Lindenberg 《Materials science & engineering. C, Materials for biological applications》2013,33(1):317-326
The aim of this study is to compare the biocompatibility of the two magnesium based alloys LAE442 and LANd442 with that of titanium. For this purpose, cylindrical implants were introduced into the medullary cavity of rabbit's tibiae for 4 and 8 weeks. Animals without any implant served as a control. In the follow-up, clinical, X-ray and μCT-investigations were performed to evaluate the reactions of the bone towards the implanted materials. After euthanasia, ex vivo μCT- and histological investigations were performed to verify the results of the in vivo tests. It could be shown that all materials induce changes in the bone. Whereas LANd442 caused the most pronounced reactions, such as increasing bone volume and bone porosity and decreasing bone density, titanium showed the most bone–implant contact by forming trabeculae. The tibiae of rabbits without implants also reacted by forming cavities, it is therefore assumed that the surgery method itself influences the bone. 相似文献
246.
247.
248.
All-optical synchronization and mode locking of solid-state lasers with nonlinear semiconductor Fabry-Perot mirrors 总被引:1,自引:0,他引:1
Seitz W. Ell R. Morgner U. Kaertner F.X. 《IEEE journal of selected topics in quantum electronics》2003,9(4):1093-1101
The dynamics of laser oscillators can be directly accessed by modulating the intracavity losses. The authors present a new approach of optically driven loss modulation by means of a nonlinear semiconductor mirror based on a Fabry-Pe/spl acute/rot structure [Fabry-Pe/spl acute/rot modulator (FPM)]. The modulation depth of this device can be several percent and the response time is dominated by the recombination time of the generated free carriers inside the semiconductor, which can be reduced by ion implantation. This paper reviews the design of the FPMs and their optical characterization via spectrally resolved two-color pump-probe spectroscopy. Applications of the FPM are the synchronization of the pulse trains of independent mode-locked laser oscillators. The authors demonstrate the synchronization of a ps-Nd:YVO/sub 4/ laser to a fs-Ti:sapphire laser in a master-slave configuration and show experiments on the carrier-envelope phase relationship between the two synchronized pulse trains. Finally, they show that it is possible to actively mode lock a solid-state laser by an optically driven FPM. The resulting pulsewidths of the actively mode-locked Nd:YVO/sub 4/ laser are as short as 6 ps, which is comparable to passively generated pulses. 相似文献
249.
A Langenbucher B Seitz MM Kus E Vilchis GO Naumann 《Canadian Metallurgical Quarterly》1998,29(2):106-113
Seven right-handed participants performed bimanual circling movements in either a symmetrical or an asymmetrical coordination mode. Movements were paced with an auditory metronome at predetermined frequencies corresponding to transition frequency, where asymmetrical patterns became unstable, or at two-thirds transition frequency where both symmetrical and asymmetrical patterns were stable. The pacing tones were presented in either a high (1000 Hz) or low (500 Hz) pitch, and the percentage of high-pitched tones during a 20 s trial varied between 0% and 70%. Participants were instructed to count the number of high-pitched pacing tones that occurred during a trial of bimanual circling. Overall, the symmetrical pattern was more stable than the asymmetrical pattern at both frequencies. Errors on the tone-counting task were significantly higher during asymmetrical circling than symmetrical circling but only at the transition movement frequency. The results suggest that cognitive processes play a role in maintaining coordination patterns within regions of instability. 相似文献
250.
Eberhard Seitz 《Advanced Performance Materials》1994,1(1):87-117
Conclusion Materials research and development are prerequisites for improving existing technologies and implementing new technologies. Science and industry in Germany agree to this view and cooperate on a work sharing basis financially supported by industry, Federal and State Government Agencies. If these is mutual benefit there are also bilateral and multilateral cooperations. 相似文献