全文获取类型
收费全文 | 387篇 |
免费 | 23篇 |
专业分类
电工技术 | 1篇 |
综合类 | 1篇 |
化学工业 | 217篇 |
金属工艺 | 3篇 |
机械仪表 | 7篇 |
建筑科学 | 15篇 |
能源动力 | 18篇 |
轻工业 | 13篇 |
石油天然气 | 10篇 |
无线电 | 13篇 |
一般工业技术 | 72篇 |
冶金工业 | 4篇 |
自动化技术 | 36篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 55篇 |
2021年 | 75篇 |
2020年 | 16篇 |
2019年 | 16篇 |
2018年 | 14篇 |
2017年 | 15篇 |
2016年 | 27篇 |
2015年 | 8篇 |
2014年 | 24篇 |
2013年 | 26篇 |
2012年 | 28篇 |
2011年 | 28篇 |
2010年 | 12篇 |
2009年 | 9篇 |
2008年 | 16篇 |
2007年 | 7篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
排序方式: 共有410条查询结果,搜索用时 843 毫秒
91.
Dmitry V. Pergushov Ekaterina V. Remizova Peter Lindner Alexander B. Zezin Victor A. Kabanov 《Polymer》2004,45(2):367-378
The micellization of ionic amphiphilic diblock copolymers, polyisobutylene-block-poly(methacrylic acid) (PIB-b-PMAA), with a constant degree of polymerization of the non-ionic block and various degrees of polymerization of the polyelectrolyte block was examined in aqueous media by means of fluorescence spectroscopy using pyrene as a polarity probe. The molar values of the critical micellization concentration (cmc) were found to be around 2×10−6 mol/l, being nearly independent of the length of the polyelectrolyte block as well as pH (in the range 6-9) and ionic strength (≤0.5 M NaCl) while the specific cmc values varied from 20 to 100 mg/l. Small-angle neutron scattering (SANS) and dynamic light scattering (DLS) experiments provided evidence that aggregation numbers and hydrodynamic radii of the formed copolymer micelles are sensitive to variations of pH and ionic strength, indicating that these micelles might be ‘dynamic’ rather than ‘frozen’ ones. It was also shown by means of a combination of turbidimetry, analytical ultracentrifugation, fluorescence spectroscopy, SANS, and DLS that the formed copolymer micelles mixed with a strong cationic polyelectrolyte, poly(N-ethyl-4-vinylpyridinium bromide) at charge ratio Z=[+]/[−] not exceeding a certain critical value ZM<1, generate peculiar water-soluble micellar complex onion-like species, each containing a two-phase hydrophobic nucleus and a hydrophilic corona. The nucleus consists of a PIB core and a shell assembled from the fragments of water-insoluble interpolyelectrolyte complex. The corona is formed by the excess fragments of poly(sodium methacrylate) blocks not involved in complexation with poly(N-ethyl-4-vinylpyridinium bromide). 相似文献
92.
Ekaterina Buyko Erik Faessler Joachim Wermter Udo Hahn 《Computational Intelligence》2011,27(4):610-644
In our approach to event extraction, dependency graphs constitute the fundamental data structure for knowledge capture. Two types of trimming operations pave the way to more effective relation extraction. First, we simplify the syntactic representation structures resulting from parsing by pruning informationally irrelevant lexical material from dependency graphs. Second, we enrich informationally relevant lexical material in the simplified dependency graphs with additional semantic meta data at several layers of conceptual granularity. These two aggregation operations on linguistic representation structures are intended to avoid overfitting of machine learning‐based classifiers which we use for event extraction (besides manually curated dictionaries). Given this methodological framework, the corresponding JReX system developed by the Julie Lab Team from Friedrich‐Schiller‐Universität Jena (Germany) scored on 2nd rank among 24 competing teams for Task 1 in the “BioNLP’09 Shared Task on Event Extraction,” with 45.8% recall, 47.5% precision and 46.7% F1‐score on all 3,182 events. In more recent experiments, based on slight modifications of JReX and using the same data sets, we were able to achieve 45.9% recall, 57.7% precision, and 51.1% F1‐score. 相似文献
93.
Kalantari Mohammad Yu Meihua Yang Yannan Strounina Ekaterina Gu Zhengying Huang Xiaodan Zhang Jun Song Hao Yu Chengzhong 《Nano Research》2017,10(2):605-617
The rational design of nano-carriers is critical for modem enzyme immobilization for advanced biocatalysis.Herein,we report the synthesis of octadecylalkylmodified mesoporous-silica nanoparticles (C18-MSNs) with a high C18 content (~19 wt.%) and tunable pore sizes (1.6-13 nm).It is demonstrated that the increased hydrophobic content and a tailored pore size (slightly larger than the size of lipase) are responsible for the high performance of immobilized lipase.The optimized C18-MSNs exhibit a loading capacity of 711 mg/g and a specific activity 5.23 times higher than that of the free enzyme.Additionally,93% of the initial activity is retained after reuse five times,which is better than the best performance reported to date.Our findings pave the way for the robust immobilization of lipase for biocatalytic applications. 相似文献
94.
Nataliya I. Shkolnikova Lidiya A. Kutulya Tatyana G. Drushlyak Nikolay S. Pivnenko Ekaterina V. Popova Evgene Yu. Kopeychenko 《Journal of the Society for Information Display》2007,15(11):943-946
Abstract— New ferroelectric liquid crystals (FLCs) on the basis of the eutectic mixture of phenylbenzoate derivatives including chiral components (CCs) with a different number and position of carbonyl groups in their molecular core have been investigated. The ferroelectric characteristics such as the spontaneous polarization, smectic tilt angle, rotational viscosity, and repolarization time as well as their concentration dependences are analyzed. On the basis of the previous and obtained results, the influence of peculiarities of the molecular structure of CCs on mentioned properties of FLCs are generalized. 相似文献
95.
Mark R. O'Masta Ekaterina Stonkevitch Kayleigh A. Porter Phuong P. Bui Zak C. Eckel Tobias A. Schaedler 《Journal of the American Ceramic Society》2020,103(12):6712-6723
This study presents a fabrication method and identifies processing bounds for additively manufacturing (AM) ceramic matrix composites (CMCs), comprising a silicon oxycarbide (SiOC) ceramic matrix. A digital light projection printer was used to photopolymerize a siloxane-based preceramic resin containing inert ceramic reinforcement. A subsequent pyrolysis converted the preceramic polymer to SiOC. Particle reinforcements of 0 to 40% by volume in the green state were uniformly dispersed in the printed samples to study their effects on pyrolysis mass loss and shrinkage, and CMC notch sensitivity and strength. Both particle and whisker reinforcements toughened the glassy SiOC matrix (1 MPa m1/2), reaching values >3 MPa m1/2. Bending strengths of >300 MPa (>150 MPa (g cm−3)−1) and a Weibull modulus of 10 were measured on AM samples without surface finish. We identified two pore formation mechanisms that placed processing bounds on sample size and reinforcement volume fraction. Methods for increasing these bounds are discussed. With properties commensurate to traditionally processed technical ceramics, the presented process allows for free-form fabrication of high-performance AM CMC components. 相似文献
96.
97.
Ekaterina Novitskaya Steve Lee Vlado A. Lubarda Joanna McKittrick 《Materials science & engineering. C, Materials for biological applications》2013,33(2):817-823
The mechanical properties of demineralized bovine cortical femur bone were investigated by cyclic loading–unloading compression in three anatomical directions (longitudinal, radial, transverse) within the physiological strain range. The loading responses in the radial and transverse directions were nearly linear up to 2% strain, while the response in longitudinal direction was strongly non-linear in that range. The unloading responses were non-linear for each anatomical direction, giving rise to overall loading–unloading hysteresis and cyclic dissipation of energy. The mechanical properties were observed to be anisotropic: the radial direction was found to be the most energy dissipative, while the longitudinal direction appeared to be the stiffest bone direction. The cyclic loading mostly affects the bone stiffness in the radial and transverse directions, while the longitudinal direction was found to be the least affected. These anisotropic properties can be attributed to the differences in collagen fibers alignment and different microstructural architecture in three different anatomical bone directions. 相似文献
98.
Elena V. Proskurnina Ivan V. Mikheev Ekaterina A. Savinova Elizaveta S. Ershova Natalia N. Veiko Larisa V. Kameneva Olga A. Dolgikh Ivan V. Rodionov Mikhail A. Proskurnin Svetlana V. Kostyuk 《International journal of molecular sciences》2021,22(11)
Background: Fullerenes and metallofullerenes can be considered promising nanopharmaceuticals themselves and as a basis for chemical modification. As reactive oxygen species homeostasis plays a vital role in cells, the study of their effect on genes involved in oxidative stress and anti-inflammatory responses are of particular importance. Methods: Human fetal lung fibroblasts were incubated with aqueous dispersions of C60, C70, and Gd@C82 in concentrations of 5 nM and 1.5 µM for 1, 3, 24, and 72 h. Cell viability, intracellular ROS, NOX4, NFκB, PRAR-γ, NRF2, heme oxygenase 1, and NAD(P)H quinone dehydrogenase 1 expression have been studied. Results & conclusion: The aqueous dispersions of C60, C70, and Gd@C82 fullerenes are active participants in reactive oxygen species (ROS) homeostasis. Low and high concentrations of aqueous fullerene dispersions (AFD) have similar effects. C70 was the most inert substance, C60 was the most active substance. All AFDs have both “prooxidant” and “antioxidant” effects but with a different balance. Gd@C82 was a substance with more pronounced antioxidant and anti-inflammatory properties, while C70 had more pronounced “prooxidant” properties. 相似文献
99.
100.
Cover Picture: Generic Structures of Cytotoxic Liprotides: Nano‐Sized Complexes with Oleic Acid Cores and Shells of Disordered Proteins (ChemBioChem 18/2014)
下载免费PDF全文
![点击此处可从《Chembiochem : a European journal of chemical biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Jørn D. Kaspersen Jannik N. Pedersen Dr. Jon G. Hansted Dr. Søren B. Nielsen Srinivasan Sakthivel Dr. Kristina Wilhelm Dr. Ekaterina L. Nemashkalova Prof. Dr. Sergei E. Permyakov Prof. Dr. Eugene A. Permyakov Prof. Dr. Cristiano Luis Pinto Oliveira Prof. Dr. Ludmilla A. Morozova‐Roche Prof. Dr. Daniel E. Otzen Prof. Dr. Jan Skov Pedersen 《Chembiochem : a European journal of chemical biology》2014,15(18):2629-2629