全文获取类型
收费全文 | 1303篇 |
免费 | 99篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 16篇 |
综合类 | 2篇 |
化学工业 | 375篇 |
金属工艺 | 23篇 |
机械仪表 | 26篇 |
建筑科学 | 36篇 |
能源动力 | 56篇 |
轻工业 | 183篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 116篇 |
一般工业技术 | 224篇 |
冶金工业 | 79篇 |
原子能技术 | 4篇 |
自动化技术 | 258篇 |
出版年
2024年 | 2篇 |
2023年 | 32篇 |
2022年 | 91篇 |
2021年 | 119篇 |
2020年 | 46篇 |
2019年 | 44篇 |
2018年 | 73篇 |
2017年 | 58篇 |
2016年 | 69篇 |
2015年 | 57篇 |
2014年 | 56篇 |
2013年 | 108篇 |
2012年 | 92篇 |
2011年 | 104篇 |
2010年 | 68篇 |
2009年 | 77篇 |
2008年 | 57篇 |
2007年 | 47篇 |
2006年 | 36篇 |
2005年 | 25篇 |
2004年 | 29篇 |
2003年 | 16篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 18篇 |
1997年 | 17篇 |
1996年 | 11篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1970年 | 1篇 |
排序方式: 共有1406条查询结果,搜索用时 10 毫秒
31.
Alessandro Marchioni Roberto Tonelli Alessandro Andreani Gaia Francesca Cappiello Matteo Fermi Fabiana Trentacosti Ivana Castaniere Riccardo Fantini Luca Tabbì Dario Andrisani Filippo Gozzi Giulia Bruzzi Linda Manicardi Antonio Moretti Serena Baroncini Anna Valeria Samarelli Massimo Pinelli Giorgio De Santis Alessandro Stefani Daniele Marchioni Francesco Mattioli Enrico Clini 《International journal of molecular sciences》2022,23(5)
Laryngotracheal stenosis (LTS) is a complex and heterogeneous disease whose pathogenesis remains unclear. LTS is considered to be the result of aberrant wound-healing process that leads to fibrotic scarring, originating from different aetiology. Although iatrogenic aetiology is the main cause of subglottic or tracheal stenosis, also autoimmune and infectious diseases may be involved in causing LTS. Furthermore, fibrotic obstruction in the anatomic region under the glottis can also be diagnosed without apparent aetiology after a comprehensive workup; in this case, the pathological process is called idiopathic subglottic stenosis (iSGS). So far, the laryngotracheal scar resulting from airway injury due to different diseases was considered as inert tissue requiring surgical removal to restore airway patency. However, this assumption has recently been revised by regarding the tracheal scarring process as a fibroinflammatory event due to immunological alteration, similar to other fibrotic diseases. Recent acquisitions suggest that different factors, such as growth factors, cytokines, altered fibroblast function and genetic susceptibility, can all interact in a complex way leading to aberrant and fibrotic wound healing after an insult that acts as a trigger. However, also physiological derangement due to LTS could play a role in promoting dysregulated response to laryngo-tracheal mucosal injury, through biomechanical stress and mechanotransduction activation. The aim of this narrative review is to present the state-of-the-art knowledge regarding molecular mechanisms, as well as mechanical and physio-pathological features behind LTS. 相似文献
32.
33.
Pedrini Matteo Langella Valentina Battaglia Mario Alberto Zaratin Paola 《Scientometrics》2018,114(3):1227-1250
Scientometrics - In recent year, a growing attention is dedicated to the assessment of research’s social impact. While prior research has often dealt with results of research, the last decade... 相似文献
34.
Matteo Palpacelli Giacomo Palmieri Luca Carbonari David Corinaldi 《Journal of Intelligent and Robotic Systems》2018,91(2):155-163
This paper is focused on the development and validation of an error kinematic model of a mini spherical robot, aimed at its kinematic calibration. The robot is actually a spatial five-bar linkage, provided with two rotational degrees of freedom. A non-overconstrained kinematics is assumed for the robot in order to provide a simple mathematical model and allow a sensitivity analysis of all the involved geometric parameters. A simplified version of the model is proposed. It differs only for the degree of approximation. A comparison between full and reduced models is presented by means of numerical simulations, analyzing their behavior in a significant region of the robot workspace. In order to validate both of them a robot calibration is carried out on a physical prototype of the robot using a vision system, namely a fixed camera in a eye-to-hand configuration. An iterative algorithm aimed at the experimental identification of the geometric data of the robot is used. Some experimental results show the effectiveness of the study. 相似文献
35.
M Monti V Pasta D Antonucci F Boccaccini FM Di Matteo S Lucci 《Canadian Metallurgical Quarterly》1996,17(10):543-546
The Authors report their experience in the treatment of ventral hernias using a Marlex mesh moulded in an original way with a technique partially derived from plastic surgery. The complete mobilization of the umbilicus through a circular incision allows to fit this prosthesis symmetrically below the rectus abdominis muscles for the entire extension of the hernia. 相似文献
36.
Bazzicalupi C Chioccioli M Sissi C Porcù E Bonaccini C Pivetta C Bencini A Giorgi C Valtancoli B Melani F Gratteri P 《ChemMedChem》2010,5(12):1995-2005
Three novel 2,7-substituted acridine derivatives were designed and synthesized to investigate the effect of this functionalization on their interaction with double-stranded and G-quadruplex DNA. Detailed investigations of their ability to bind both forms of DNA were carried out by using spectrophotometric, electrophoretic, and computational approaches. The ligands in this study are characterized by an open-chain (L1) or a macrocyclic (L2, L3) framework. The aliphatic amine groups in the macrocycles are joined by ethylene (L2) or propylene chains (L3). L1 behaved similarly to the lead compound m-AMSA, efficiently intercalating into dsDNA, but stabilizing G-quadruplex structures poorly, probably due to the modest stabilization effect exerted by its protonated polyamine chains. L2 and L3, containing small polyamine macrocyclic frameworks, are known to adopt a rather bent and rigid conformation; thus they are generally expected to be sterically impeded from recognizing dsDNA according to an intercalative binding mode. This was confirmed to be true for L3. Nevertheless, we show that L2 can give rise to efficient π-π and H-bonding interactions with dsDNA. Additionally, stacking interactions allowed L2 to stabilize the G-quadruplex structure: using the human telomeric sequence, we observed the preferential induction of tetrameric G-quadruplex forms. Thus, the presence of short ethylene spacers seems to be essential for obtaining a correct match between the binding sites of L2 and the nucleobases on both DNA forms investigated. Furthermore, current modeling methodologies, including docking and MD simulations and free energy calculations, provide structural evidence of an interaction mode for L2 that is different from that of L3; this could explain the unusual stabilizing ability of the ligands (L2>L3>L1) toward G-quadruplex that was observed in this study. 相似文献
37.
Marco Bandini Matteo Fagioli Achille Umani‐Ronchi 《Advanced Synthesis \u0026amp; Catalysis》2004,346(5):545-548
In this paper a novel application of solid acid catalysts in the chemoselective Friedel–Crafts (FC) alkylation of indoles is reported. The optimal protocol allows highly functionalised indolyl compounds to be synthesised in excellent yields through conjugate addition of indoles with α,β‐unsaturated ketones and nitro compounds. Finally, the use of commercial Amberlyst‐15 as the heterogeneous catalyst for highly atom efficient continuous and semicontinuous Friedel–Crafts processes is described. 相似文献
38.
As an alternative to previously developed catalytic FeCrAlloy fibre mat burners based on perovskite catalysts, new catalytic burners have been developed based on Pd catalyst on lantana-stabilised Al2O3 and different fibre structures (NIT100A, NIT100S and NIT200S by ACOTECH NV). All development steps are considered, shifting from catalyst preparation (based on combustion synthesis of γ-Al2O3) to the optimisation of lantana and Pd loadings, from the definitions of the best catalyst-deposition conditions (washcoating) to the catalytic burners performances, determined in an ad hoc developed combustion chamber. The results show almost half pollutants emissions and better performance compared to various non-catalytic counterparts, especially as far as CO and NOx emissions are concerned. Some flame instability problems were though registered, especially for one of the catalytic burner mattresses employed, at low specific power inputs and excesses of air (<375 kW/m2 and <12%, respectively). Further, PdO/Pd transition is shown to influence the dynamic behaviour of the catalytic burners. 相似文献
39.
Insa Thale Sarah Maskri Lucie Grey Luca Matteo Todesca Prof. Dr. Thomas Budde Dr. Ivan Maisuls Prof. Dr. Cristian A. Strassert Prof. Dr. Oliver Koch Prof. Dr. Albrecht Schwab Prof. Dr. Bernhard Wünsch 《ChemMedChem》2023,18(2):e202200551
The Ca2+ activated K+ channel KCa3.1 is overexpressed in several human tumor cell lines, e. g. clear cell renal carcinoma, prostate cancer, non-small cell lung cancer. Highly aggressive cancer cells use this ion channel for key processes of the metastatic cascade such as migration, extravasation and invasion. Therefore, small molecules, which are able to image this KCa3.1 channel in vitro and in vivo represent valuable diagnostic and prognostic tool compounds. The [18F]fluoroethyltriazolyl substituted senicapoc was used as positron emission tomography (PET) tracer and showed promising properties for imaging of KCa3.1 channels in lung adenocarcinoma cells in mice. The novel senicapoc BODIPY conjugates with two F-atoms ( 9 a ) and with a F-atom and a methoxy moiety ( 9 b ) at the B-atom led to the characteristic punctate staining pattern resulting from labeling of single KCa3.1 channels in A549-3R cells. This punctate pattern was completely removed by preincubation with an excess of senicapoc confirming the high specificity of KCa3.1 labeling. Due to the methoxy moiety at the B-atom and the additional oxyethylene unit in the spacer, 9 b exhibits higher polarity, which improves solubility and handling without reduction of fluorescence quantum yield. Docking studies using a cryo-electron microscopy (EM) structure of the KCa3.1 channel confirmed the interaction of 9 a and 9 b with a binding pocket in the channel pore. 相似文献
40.
The influence of drying air temperature on the physical properties of dried and rehydrated eggplant 总被引:1,自引:0,他引:1
Paola Russo Giuseppina Adiletta Marisa Di Matteo 《Food and Bioproducts Processing》2013,91(3):249-256
Drying processes generally cause volume and surface change of foodstuffs. Information on the porous structure and the mechanical properties of dried food products is needed for determining food quality, process design and estimating properties such as density and moisture diffusivity.In this work we investigated the structural changes induced in eggplant by convective air drying at four different temperatures (40, 50, 60 and 70 °C) and their effect on the subsequent rehydration process. Drying and rehydration kinetic curves were also measured.The changes in physical properties, such as porosity, pore-size distribution and bulk density were determined by Hg porosimetry, scanning electron microscopy and optical microscopy while their effect on the textural characteristics by dynamometric measurements.As expected, the increase of the drying air temperature causes shorter drying times. The drying temperature influences strongly the microstructure of dried samples: the porosity increases with the air temperature, but the structure is better preserved at intermediate temperature (60 °C) as confirmed by the lower firmness values with respect to the other dehydrated samples (40, 50 and 70 °C). In these latter, the longer drying time and the higher temperature, respectively, causes the development of a wrinkled structure. In particular, at 70 °C the structure of dehydrated samples appears totally broken with a consequent faster water uptake during rehydration. 相似文献