全文获取类型
收费全文 | 349篇 |
免费 | 31篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 170篇 |
金属工艺 | 5篇 |
机械仪表 | 6篇 |
建筑科学 | 23篇 |
能源动力 | 6篇 |
轻工业 | 91篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 7篇 |
一般工业技术 | 34篇 |
冶金工业 | 11篇 |
自动化技术 | 26篇 |
出版年
2023年 | 4篇 |
2022年 | 20篇 |
2021年 | 18篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 19篇 |
2017年 | 18篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 16篇 |
2013年 | 27篇 |
2012年 | 26篇 |
2011年 | 34篇 |
2010年 | 27篇 |
2009年 | 20篇 |
2008年 | 22篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 11篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有381条查询结果,搜索用时 15 毫秒
11.
Shelley Waters Silvia Lee Ibnu Ariyanto Shay Leary Kylie Munyard Silvana Gaudieri Ashley Irish Richard J. N. Allcock Patricia Price 《International journal of molecular sciences》2022,23(21)
Around 80% of adults worldwide carry human cytomegaloviris (HCMV). The HCMV gene UL18 is a homolog of HLA class I genes and encodes a protein with high affinity for the NK and T-cell cytotoxicity inhibitor LIR-1. UL18 was deep sequenced from blood, saliva or urine from Indonesian people with HIV (PWH) (n = 28), Australian renal transplant recipients (RTR) (n = 21), healthy adults (n = 7) and neonates (n = 4). 95% of samples contained more than one variant of HCMV UL18, as defined by carriage of nonsynonymous variations. When aligned with immunological markers of the host’s burden of HCMV, the S318N variation associated with high levels of antibody reactive with HCMV lysate in PWH over 12 months on antiretroviral therapy. The A107T variation associated with HCMV antibody levels and inflammatory biomarkers in PWH at early timepoints. Variants D32G, D248N, V250A and E252D aligned with elevated HCMV antibody levels in RTR, while M191K, E196Q and F165L were associated with HCMV-reactive T-cells and proportions of Vδ2− γδ T-cells—populations linked with high burdens of HCMV. We conclude that UL18 is a highly variable gene, where variation may alter the persistent burden of HCMV and/or the host response to that burden. 相似文献
12.
Zachary Cooper Casey Simons Silvana Martini 《Journal of the American Oil Chemists' Society》2019,96(11):1205-1218
The objective of this work was to identify the effects that milk phospholipids (PL) have on crystallization of anhydrous milk fat (AMF). Three mixtures were prepared by adding 0%, 0.01%, and 0.1% PL to AMF. Each mixture was crystallized for 90 min at 24, 26, and 28 °C. The solid fat content was measured as a function of time and fitted to the Avrami equation. Melting point, thermal behavior, viscoelastic properties, and crystal morphology were all measured at 90 min. All assays were repeated, as well as hardness, after being stored at 5 °C for 48 hours. Samples containing PL showed slower crystallization as concentration increased especially at higher temperatures (26 and 28 °C). The addition of PL caused a difference in crystal morphology resulting in visibly larger crystals at 90 min. The elasticity and hardness at 90 min were influenced by the addition of PL at 24 °C with lower values obtained in samples with PL compared to the AMF alone. No differences in hardness nor in elasticity was observed for samples crystallized at 26 and 28 °C. A decrease in melting enthalpy was observed in samples with PL indicating a reduction in crystallization at all temperatures, which was supported by crystal morphology. 相似文献
13.
Alejo Aguirre Adrián L. Bonivardi Silvana R. Matkovic Laura E. Briand Sebastián E. Collins 《Topics in Catalysis》2011,54(1-4):229-235
The decomposition of acetic anhydride in liquid phase on a fosfotungstic Wells–Dawson heteropoly acid (HPA) was investigated by in situ ATR-FTIR spectroscopy. Transient and concentration-modulation excitation spectroscopy (MES) experiments in combination with phase-sensitive detection (PSD) were used to monitor the solid–liquid interface. The MES method is based on the periodic variation of a parameter of the reaction media such as, the reactant concentration. That periodic alteration causes varying infrared signals of the surface adsorbed species that are subsequently demodulated with the PSD methodology. Thus, the separation of the static signals from the changing ones is achieved, and species with different response can be observed in the spectra. Using MES-PSD coupled with ATR-FTIR, acetic anhydride was observed to decompose to acetic acid, acetate and acyl [CH3C(O)+] species, involving Brønsted acid sites of the HPA catalyst. The CH3C(O)+ is a very unstable intermediate species and it is the key intermediate in the Friedel–Crafts acylation reactions. Moreover, the acetate groups are spectator species since remain strongly adsorbed on the catalyst surface and do not further react. 相似文献
14.
Carlo Beatrice Chiara Guido Pierpaolo Napolitano Silvana Di Iorio Nicola Del Giacomo 《Fuel》2011,90(5):2039-2044
Results of a research project aimed at studying the capability to develop a method (economic and simple) for on-board biodiesel blending detection are described. The method is based on the direct measurement of the Indicated Mean Effective Pressure (IMEP).The study was carried out on a 2.0L four-cylinder “torque-controlled” Euro 5 diesel engine for passenger car (PC) application. This engine, equipped with instrumented glow plug for combustion closed-loop control, represents the state of the art of the diesel engine control technology.Two biodiesels were chosen for the experiments: a rapeseed methyl-ester (RME) and an aged RME, while the conventional diesel fuel was an European (EU) certification diesel fuel.Results indicate generally a good response in blending detection of the method. However, in order to attain an acceptable accuracy, a pre-calibration appears necessary. 相似文献
15.
Walter F Schroeder Silvana L Asmussen Wayne D Cook Claudia I Vallo 《Polymer International》2011,60(9):1362-1369
The efficiency of 4,4′‐bis(N,N‐diethylamino)benzophenone (DEABP) for the polymerization of dimethacrylate monomers in thick sections ( 1 – 2 mm) was studied. DEABP (λmax = 365 nm) represents a complete initiating system as it contains both ketone and amine functional groups. During irradiation, DEABP photobleaches at a fast rate causing deeper penetration of light through the underlying layers, but the photoinitiation efficiency (rate of polymerization per photon absorption rate) is relatively poor. As a result, irradiation of methacrylate monomers at 365 nm results in a slow average polymerization rate and a reduced monomer conversion for thick sections due to the light attenuation caused by the high absorptivity of DEABP and photolysis products. These results highlight the inherent interlinking of light attenuation and photobleaching rate in polymerization of thick sections. Copyright © 2011 Society of Chemical Industry 相似文献
16.
Vincenzo Leone Silvana Canzano Pasquale Iovino Sante Capasso 《Journal of Porous Materials》2012,19(4):449-453
The sorption of humic acids (HA) on zeolite-feldspar-bearing Phlegraean Yellow Tuff enriched with calcium ions has been investigated at neutral pH both on fixed-bed columns and in batch. A two-step sorption kinetics and a relatively long time to reach the equilibrium were observed in batch. In line with this behaviour, the breakthrough curves and shipping curves from exhaust columns showed distinctive properties that cannot be easily modelled by the common mass balance equations; noteworthy, the breakthrough curves were dependent on the space velocity also for very slow processes and the bed sorption capacity decreased linearly with the space velocity. Moreover, after an initial high-rate burst, HA desorption from exhausted columns proceeded at a very slow rate, particularly so for columns loaded with higher amounts of HA. 相似文献
17.
Prof. Silvia Rivara Dr. Daniele Pala Dr. Alessio Lodola Prof. Marco Mor Dr. Valeria Lucini Dr. Silvana Dugnani Prof. Francesco Scaglione Dr. Annalida Bedini Dr. Simone Lucarini Prof. Giorgio Tarzia Prof. Gilberto Spadoni 《ChemMedChem》2012,7(11):1954-1964
The design of compounds selective for the MT1 melatonin receptor is still a challenging task owing to the limited knowledge of the structural features conferring selectivity for the MT1 subtype, and only few selective compounds have been reported so far. N‐(Anilinoalkyl)amides are a versatile class of melatonin receptor ligands that include nonselective MT1/MT2 agonists and MT2‐selective antagonists. We synthesized a new series of N‐(anilinoalkyl)amides bearing 3‐arylalkyloxy or 3‐alkyloxy substituents at the aniline ring, looking for new potent and MT1‐selective ligands. To evaluate the effect of substituent size and shape on binding affinity and intrinsic activity, both flexible and conformationally constrained derivatives were prepared. The phenylbutyloxy substituent gave the best result, providing the partial agonist 4 a , which was endowed with high MT1 binding affinity (pKi=8.93) and 78‐fold selectivity for the MT1 receptor. To investigate the molecular basis for agonist recognition, and to explain the role of the 3‐arylalkyloxy substituent, we built a homology model of the MT1 receptor based on the β2 adrenergic receptor crystal structure in its activated state. A binding mode for MT1 agonists is proposed, as well as a hypothesis regarding the receptor structural features responsible for MT1 selectivity of compounds with lipophilic arylalkyloxy substituents. 相似文献
18.
Felipe R. Boni Filipe V. Ferreira Ivanei F. Pinheiro Silvana A. Rocco Mauricio L. Sforça Liliane M. F. Lona 《应用聚合物科学杂志》2020,137(45):49416
Here, an alternative route to successfully synthesize polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) is reported. Steglich esterification was used as an effective, metal free approach for coupling carboxylic terminated PS and the hydroxyl end-functionalized PMMA chains obtained by nitroxide-mediated polymerization and atom transfer radical polymerization, respectively. α-Functionalization was obtained using 4,4′-azobis(4-cyanovaleric acid) and 2,2,2-tribromoethanol as initiators. The synthesis of PS-b-PMMA was confirmed by gel permeation chromatography and nuclear magnetic resonance (NMR), while the dependence of the diffusion coefficients of the polymers (PS, PMMA, PS/PMMA blend, and PS-b-PMMA) with their corresponding molecular weights was discussed based on the results of atomic force microscopy-based infrared spectroscopy, differential scanning calorimetry, and spectra of diffusion-ordered NMR spectroscopy. Differently from PS-b-PMMA, a partial segregation was observed for the PS/PMMA blend, affecting its thermal behavior and diffusion coefficient. The study here presented provides an easier and efficient strategy for the synthesis of PS-b-PMMA and new insights into the diffusion of polymers. 相似文献
19.
Prof. Chiara Brullo Dr. Federica Rapetti Prof. Silvana Alfei Dr. Irena Maric Dr. Francesca Rizzelli Dr. Marina Mapelli Dr. Camillo Rosano Dr. Maurizio Viale Prof. Olga Bruno 《ChemMedChem》2020,15(11):961-969
Even though immunotherapy has radically changed the search for anticancer therapies, there are still many different pathways that are open to intervention with traditional small molecules. To expand our investigation in the anticancer field, we report here a new series of compounds in which our previous pyrazole and imidazopyrazole scaffolds are linked to a differently decorated phenyl ring through an acylhydrazone linker. Preliminary tests on the library were performed at the National Cancer Institute (USA) against the full NCI 60 cell panel. The best compounds among the imidazopyrazole series were then tested by immunofluorescence staining for their inhibition of cell proliferation, apoptosis induction, and their effect on the cell cycle and on microtubules. Two compounds, in particular 4-benzyloxy-3-methoxybenzyliden imidazopyrazole-7-carbohydrazide showed good growth inhibition, with IC50 values in the low-micromolar range, and induced apoptosis. Both compounds altered the cell-cycle phases with the appearance of polyploid cells. Immunofluorescence analysis evidenced microtubules alterations; tubulin polymerization assays and docking studies suggested the tubulin system to be the possible, although not exclusive, target of the new acylhydrazone series reported here. 相似文献
20.
Joseph Cooney Isaac Hilton Melissa Marsh Annalisa Jones Silvana Martini 《Journal of the American Oil Chemists' Society》2023,100(3):225-236
The objective of this study was to evaluate the effect of cannabidiol (CBD) on the crystallization behavior and physical properties of various fats. Anhydrous milk fat (AMF), palm oil (PO), palm kernel oil (PKO), and cocoa butter (CB) were chosen for this study, for their unique crystallization behaviors. CBD was added at 1 and 2.5% wt/wt to these fats, and the crystallization behavior was evaluated at 26°C for AMF and PO and at 22°C for PKO and CB. Control samples with no CBD were prepared and evaluated as well. Results show that CBD delayed the crystallization of all fats with the least effect observed for the PO. Slight increases in crystal size were observed with the addition of CBD for all samples. CBD did not affect the melting profile of AMF or CB, but it increased the peak temperature of PO and decreased the enthalpy of PKO. Similarly, hardness was only affected by CBD in PO samples, with harder materials obtained for samples containing 2.5% CBD. The same trend was observed for elasticity. In addition, the elasticity of AMF increased with the addition of CBD but not its hardness. Overall, this study indicates that the effect of CBD on fat crystallization is highly dependent on the type of fat used. Producers of fat-based products that are willing to include CBD in their formulations must carefully control processing conditions to ensure product quality. 相似文献