全文获取类型
收费全文 | 1214篇 |
免费 | 73篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 11篇 |
化学工业 | 542篇 |
金属工艺 | 12篇 |
机械仪表 | 24篇 |
建筑科学 | 32篇 |
矿业工程 | 1篇 |
能源动力 | 49篇 |
轻工业 | 206篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 59篇 |
一般工业技术 | 199篇 |
冶金工业 | 55篇 |
原子能技术 | 4篇 |
自动化技术 | 86篇 |
出版年
2024年 | 3篇 |
2023年 | 29篇 |
2022年 | 84篇 |
2021年 | 103篇 |
2020年 | 34篇 |
2019年 | 40篇 |
2018年 | 56篇 |
2017年 | 46篇 |
2016年 | 53篇 |
2015年 | 45篇 |
2014年 | 48篇 |
2013年 | 68篇 |
2012年 | 59篇 |
2011年 | 86篇 |
2010年 | 73篇 |
2009年 | 49篇 |
2008年 | 77篇 |
2007年 | 64篇 |
2006年 | 46篇 |
2005年 | 24篇 |
2004年 | 21篇 |
2003年 | 26篇 |
2002年 | 21篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 12篇 |
1998年 | 4篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1977年 | 6篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1970年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有1288条查询结果,搜索用时 15 毫秒
101.
Juskanič Dominik Mištinová Jana Poláková Hollý Samuel Sekerešová Monika Koleják Kamil Pátrovič Lukáš 《Magma (New York, N.Y.)》2022,35(1):45-52
Magnetic Resonance Materials in Physics, Biology and Medicine - Oncometabolite D-2-hydroxyglutarate (2HG) is pooled in isocitrate dehydrogenase (IDH)-mutant glioma cells. Detecting 2HG by MR... 相似文献
102.
Maria Bartosova David Ridinger Iva Marinovic Jana Heigwer Conghui Zhang Eszter Levai Jens H. Westhoff Franz Schaefer Stefan Terjung Georg Hildenbrand Damir Krunic Felix Bestvater Michael Hausmann Claus Peter Schmitt Sotirios G. Zarogiannis 《International journal of molecular sciences》2021,22(15)
Endothelial and epithelial barrier function is crucial for the maintenance of physiological processes. The barrier paracellular permeability depends on the composition and spatial distribution of the cell-to-cell tight junctions (TJ). Here, we provide an experimental workflow that yields several layers of physiological data in the setting of a single endothelial cell monolayer. Human umbilical vein endothelial cells were grown on Transwell filters. Transendothelial electrical resistance (TER) and 10 kDa FITC dextran flux were measured using Alanyl-Glutamine (AlaGln) as a paracellular barrier modulator. Single monolayers were immunolabelled for Zonula Occludens-1 (ZO-1) and Claudin-5 (CLDN5) and used for automated immunofluorescence imaging. Finally, the same monolayers were used for single molecule localization microscopy (SMLM) of ZO-1 and CLDN5 at the nanoscale for spatial clustering analysis. The TER increased and the paracellular dextran flux decreased after the application of AlaGln and these functional changes of the monolayer were mediated by an increase in the ZO-1 and CLDN5 abundance in the cell–cell interface. At the nanoscale level, the functional and protein abundance data were accompanied by non-random increased clustering of CLDN5. Our experimental workflow provides multiple data from a single monolayer and has wide applicability in the setting of paracellular studies in endothelia and epithelia. 相似文献
103.
MnO-
4 (0.4 mmol/g)-exchanged Mg-Al-hydrotalcite is an active and highly selective catalyst for the oxidation of benzyl alcohol to benzaldehyde by tert-butyl hydroperoxide under reflux in the absence of solvent. It also shows high activity for the oxidation of benzaldehyde to benzoic acid. The higher the Mg/Al ratio, the higher is the catalytic activity (in both the reactions) and basicity of the hydrotalcite catalyst. 相似文献
104.
Claudia Voigt Tilo Zienert Pia Schubert Christos G. Aneziris Jana Hubálková 《Journal of the American Ceramic Society》2014,97(7):2046-2053
The aim of this study was to discuss the influence of different filter surface chemistries on the properties of foam filters. For reliable results, it is essential to ensure comparable structural properties (cell size and strut thickness) for all different surface chemistries (Al2O3, MgAl2O4, 3Al2O3·2SiO2, SiO2, and TiO2) possess the same structural properties (cell size and strut thickness). Filters made of 100% of the investigated materials and alumina skeletons coated with the investigated materials were prepared. The coated alumina samples were sintered in one and two steps. The processing route with two sintering steps resulted in improved mechanical properties and comparable shrinkage and strut thickness. The 100% bulk foams possessed different pore sizes due to the differences of the material shrinkage. In this study, a comparison of the experimental investigated properties of the ceramic foam filters and the theoretically calculated values for foam materials derived from the bulk material properties is established. 相似文献
105.
Domenico Maiorano Jana El Etri Camille Franchet Jean-Sbastien Hoffmann 《International journal of molecular sciences》2021,22(8)
DNA can experience “replication stress”, an important source of genome instability, induced by various external or endogenous impediments that slow down or stall DNA synthesis. While genome instability is largely documented to favor both tumor formation and heterogeneity, as well as drug resistance, conversely, excessive instability appears to suppress tumorigenesis and is associated with improved prognosis. These findings support the view that karyotypic diversity, necessary to adapt to selective pressures, may be limited in tumors so as to reduce the risk of excessive instability. This review aims to highlight the contribution of specialized DNA polymerases in limiting extreme genetic instability by allowing DNA replication to occur even in the presence of DNA damage, to either avoid broken forks or favor their repair after collapse. These mechanisms and their key regulators Rad18 and Polθ not only offer diversity and evolutionary advantage by increasing mutagenic events, but also provide cancer cells with a way to escape anti-cancer therapies that target replication forks. 相似文献
106.
Rieke Himstedt Dr. Silke Wagner Dr. Robert J. R. Jaeger Dr. Michèle-Laure Lieunang Watat Dr. Jana Backenköhler Dr. Zeljka Rupcic Prof. Dr. Marc Stadler Prof. Dr. Peter Spiteller 《Chembiochem : a European journal of chemical biology》2020,21(11):1613-1620
Mycenarubin C, a previously unknown red pyrroloquinoline alkaloid, was isolated from fruiting bodies of the mushroom Mycena rosea and its structure was elucidated mainly by NMR spectroscopy and mass spectrometry. Unlike mycenarubin A, the major pyrroloquinoline alkaloid in fruiting bodies of M. rosea, mycenarubin C, contains an eight-membered ring with an additional C1 unit that is hitherto unprecedented for pyrroloquinoline alkaloids known in nature. Incubation of mycenarubin A with an excess of formaldehyde revealed that mycenarubin C was generated nearly quantitatively from mycenarubin A. An investigation into the formaldehyde content of fresh fruiting bodies of M. rosea showed the presence of considerable amounts of formaldehyde, with values of 5 μg per gram of fresh weight in fresh fruiting bodies. Although mycenarubin C did not show bioactivity against selected bacteria and fungi, formaldehyde inhibits the growth of the mycoparasite Spinellus fusiger at concentrations present in fruiting bodies of M. rosea. Therefore, formaldehyde might play an ecological role in the chemical defence of M. rosea against S. fusiger. In turn, S. fusiger produces gallic acid—presumably to detoxify formaldehyde by reaction of this aldehyde with amino acids and gallic acid to Mannich adducts. 相似文献
107.
Monika Bosacka Anna Blonska-Tabero Elzbieta Filipek Jana Luxová Petra Šulcová 《Ceramics International》2021,47(17):24607-24614
A new pyrophosphate(V) of the formula Co5Cr2(P2O7)4 was obtained in the system Co2P2O7–Cr4(P2O7)3 as a result of solid-state reactions taking place between different reactants. The new compound crystallizes in the orthorhombic system and belongs to the family of pyrophosphates of the general formula M52+M23+(P2O7)4 and is probably isostructural with Fe52+Fe23+(P2O7)4. Powder diffraction pattern, infrared spectrum and SEM image of the new compound were presented. As a new potential inorganic pigment, Co5Cr2(P2O7)4 was tested for its thermal stability, particle size distribution and colour properties, which were studied both for powder and after introduction into organic matrix and leadless ceramic glaze. The colour of Co5Cr2(P2O7)4 powder was defined as deep grey with the colour coordinates L*/a*/b* = 60.63/-1.42/-3.41 and according to the hue angle (h° = 247.39°) it belongs to the blue region. Co5Cr2(P2O7)4, with its relatively high thermal stability (t m = 1230 ± 10 °C) and appropriate colour properties, is a good candidate to be used as inorganic pigment for colouring of acrylic paints. In the case of leadless glaze, the obtained compound acts as a dye. 相似文献
108.
109.
110.
Comprehensive study on surfactant role on silver nanoparticles (NPs) prepared via modified Tollens process 总被引:1,自引:0,他引:1
Jana Soukupov Libor Kvítek Ale Pan
ek Tajana Nev
n Radek Zboil 《Materials Chemistry and Physics》2008,111(1):77-81
Surfactants represent not only commonly used wetting agents but also substances that can be used as growth modifiers in the process of solid nanoparticle (NP) preparation. In this study we report influential character of different types of surfactants – i.e. ionic (SDS, CTAC) and non-ionic (Tween 80) – on fundamental characteristics of silver NPs, which were prepared by a modified Tollens process. The influential character of surfactants was evaluated throughout a reasonable improvement of the polydispersity (in the case of the tested non-ionic surfactants from 8.5% even down to 2.5%) and in the case of ionic surfactant, SDS and CTAC, also significant change of zeta potential (from −20 to −50 mV for the highest tested concentration of SDS). A slight influence of the tested surfactants was observed on the sizes of the prepared silver NPs. Therefore the obtained results from the performed surfactant-assisted syntheses revealed a possibility how to tailor silver NPs by means of their polydispersity and zeta potential according to the application demands. 相似文献