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71.
Rana Noor Arun K. Srivastava 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2014,18(10):1865-1871
We show that the category \(L\) - \(\mathbf{Top}_{0}\) of \(T_{0}\) - \(L\) -topological spaces is the epireflective hull of Sierpinski \(L\) -topological space in the category \(L\) - \(\mathbf{Top}\) of \(L\) -topological spaces and the category \(L\) - \(\mathbf{Sob}\) of sober \(L\) -topological spaces is the epireflective hull of Sierpinski \(L\) -topological space in the category \(L\) - \(\mathbf{Top}_{0}\) . 相似文献
72.
Quanlong Yang Sergey Kruk Yuehong Xu Qingwei Wang Yogesh Kumar Srivastava Kirill Koshelev Ivan Kravchenko Ranjan Singh Jiaguang Han Yuri Kivshar Ilya Shadrivov 《Advanced functional materials》2020,30(4)
All‐dielectric metasurfaces have become a new paradigm for flat optics as they allow flexible engineering of the electromagnetic space of propagating waves. Such metasurfaces are usually composed of individual subwavelength elements embedded into a host medium or placed on a substrate, which often diminishes the quality of the resonances. The substrate imposes limitations on the metasurface functionalities, especially for infrared and terahertz frequencies. Here a novel concept of membrane Huygens' metasurfaces is introduced. The metasurfaces feature an inverted design, and they consist of arrays of holes made in a thin membrane of high‐index dielectric material, with the response governed by the electric and magnetic Mie resonances excited within dielectric domains of the membrane. Highly efficient transmission combined with the 2π phase coverage in the freestanding membranes is demonstrated. Several functional metadevices for wavefront control are designed, including beam deflector, a lens, and an axicon. Such membrane metasurfaces provide novel opportunities for efficient large‐area metadevices, whose advanced functionality is defined by structuring rather than by chemical composition. 相似文献
73.
74.
Tamarind kernel polysaccharide (TKP), isolated by fractionation of tamarind kernel powder, was heated at 153°C for 5 h in presence of 0.074% hydrochloric acid. The resulting product was fractionated to yield a homogeneous dextrin which on hydrolysis produced D -xylose, D -galactose and D -glucose in the molar ratio of 2:1:10. Methylation of the dextrin followed by hydrolysis yielded 2,3,4-tri-O-methyl-D -xylose (2 moles); 2,3,4,6-tetra-O-methyl-D -glucose (1 mole); 2,3,4,6-tetra-O-methyl-D -galactose (1 mole); 2,3,4-tri-O-methyl-D -glucose (1 mole); 2,3,6-tri-O-methyl-D -glucose (4 moles); 2,3-di-O-methyl-D -glucose (4 moles); and 2-O-methyl-D -glucose (trace amounts). Upon oxidation of the dextrin with sodium metaperiodate, 1.4 moles of the oxidant was consumed with concomitant liberation of 0.38 mole of formic acid. Reduction of the oxopolysaccharide with sodium borohydride followed by acid hydrolysis of the polyol produced erythritol, glycerol and ethylene glycol in the molar ratio of 8:3:2. The above results suggest that the main reaction during dextrinization of TKP is that of hydrolysis. The side branches of the polymer are hydrolyzed to a greater extent than its backbone. Transglycosidation, which is the predominant reaction in starch dextrinization, takes place only to a small extent. 相似文献
75.
Gideon L. Smith Ayush K. Srivastava Aliaksandra A. Reutovich Nathan J. Hunter Paolo Arosio Artem Melman Fadi Bou-Abdallah 《International journal of molecular sciences》2022,23(11)
Most in vitro iron mobilization studies from ferritin have been performed in aqueous buffered solutions using a variety of reducing substances. The kinetics of iron mobilization from ferritin in a medium that resembles the complex milieu of cells could dramatically differ from those in aqueous solutions, and to our knowledge, no such studies have been performed. Here, we have studied the kinetics of iron release from ferritin in fresh yeast cell lysates and examined the effect of cellular metabolites on this process. Our results show that iron release from ferritin in buffer is extremely slow compared to cell lysate under identical experimental conditions, suggesting that certain cellular metabolites present in yeast cell lysate facilitate the reductive release of ferric iron from the ferritin core. Using filtration membranes with different molecular weight cut-offs (3, 10, 30, 50, and 100 kDa), we demonstrate that a cellular component >50 kDa is implicated in the reductive release of iron. When the cell lysate was washed three times with buffer, or when NADPH was omitted from the solution, a dramatic decrease in iron mobilization rates was observed. The addition of physiological concentrations of free flavins, such as FMN, FAD, and riboflavin showed about a two-fold increase in the amount of released iron. Notably, all iron release kinetics occurred while the solution oxygen level was still high. Altogether, our results indicate that in addition to ferritin proteolysis, there exists an auxiliary iron reductive mechanism that involves long-range electron transfer reactions facilitated by the ferritin shell. The physiological implications of such iron reductive mechanisms are discussed. 相似文献
76.
Srivastava Sanjay; Tamir Maya; McGonigal Kelly M.; John Oliver P.; Gross James J. 《Canadian Metallurgical Quarterly》2009,96(4):883
There is growing interest in understanding how emotion regulation affects adaptation. The present study examined expressive suppression (which involves inhibiting the overt expression of emotion) and how it affects a critical domain of adaptation, social functioning. This investigation focused on the transition to college, a time that presents a variety of emotional and social challenges. Analyses focused on 2 components of suppression: a stable component, representing individual differences expressed both before and after the transition, and a dynamic component, representing variance specific to the new college context. Both components of suppression predicted lower social support, less closeness to others, and lower social satisfaction. These findings were robustly corroborated across weekly experience reports, self-reports, and peer reports and are consistent with a theoretical framework that defines emotion regulation as a dynamic process shaped by both stable person factors and environmental demands. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
77.
Gaurav Shukla Abhijeet Srivastava Anugula Nagaraju Keshav Raghuvanshi Maya Shankar Singh 《Advanced Synthesis \u0026amp; Catalysis》2015,357(18):3969-3976
The direct α‐Csp2 H functionalization and thiomethylation of α‐oxoketene dithioacetals (DTAs) has been accomplished with dimethyl sulfoxide (DMSO) in the presence of iodine and a copper(I) salt for the first time. A prerequisite is the in situ iodination of the α‐Csp2 atom of dithioacetals that could offer other reaction channels. The operationally simple one‐pot protocol includes region‐defined consecutive iodination and sulfenylation of the challenging α‐Csp2 H bond of dithioacetals employing cheap and readily available reagents. DMSO here plays a dual role as thiomethyl source and solvent.
78.
Sangita Kumari Karthikeyan Pillai Asha Sharma Ella Mihevc Amit Srivastava Albert Chan 《Particulate Science and Technology》2015,33(5):562-566
Cryogenic aerosol cleaning is a dry cleaning method used in the back end of line (BEOL) semiconductor manufacturing to remove defects from planar hydrophobic surfaces such as SiCOH and SiCxNyHz. Cryogenic aerosol cleaning is preferred over conventional wet cleaning methods as it is a non-contact cleaning method, which uses inert gases to generate sub-micrometer-sized solid aerosol particles that physically remove nanometer-sized contaminants on wafer surfaces. Particle removal mechanism involves detachment of the particles upon impact with aerosol, diffusion, and finally entrainment away from the wafer. In BEOL metal line patterning, particles on the dielectric isolation surfaces translate through the subsequent lithography and copper fill steps in to single or multiple metal line open defects that are yield killers. In this study, we show that the particle removal performance of the standard aerosol cleaning can be enhanced by pre-heating the wafer and use of a higher molecular weight inert gas, namely Ar, for aerosol generation. Both the addition of a Pre-heat step and the use of Ar as the aerosol source showed 47–52% reduction in single and multiple line opens detected through wafer electrical tests during high volume semiconductor manufacturing process. 相似文献
79.
Noncovalent assembly of carbon nanofiber–layered double hydroxide as a reinforcing hybrid filler in thermoplastic polyurethane–nitrile butadiene rubber blends 下载免费PDF全文
A new synthetic route was applied to develop carbon nanofiber (CNF)–layered double hydroxide (LDH) hybrid through a noncovalent assembly using sodium dodecyl sulfate as bridging linker between magnesium–aluminum LDH and CNF and then characterized. Furthermore, this hybrid was used as nanofiller in thermoplastic polyurethane–acrylonitrile butadiene rubber (TN; 1:1 w/w) blend. Mechanical measurements showed that the 0.50 wt % hybrid loaded TN blend exhibited the maximum improvements in the elongation at break, tensile strength, and storage modulus of 1.51 times and 167 and 261% (25 °C), respectively. Differential scanning calorimetric analysis and thermogravimetric analysis showed maximum improvements in the melting temperature (5 °C), crystallization temperature (17 °C), and thermal stability (14 °C) in the 0.50 wt % surfactant modified carbon nanofiber–LDH loaded blend compared to the neat blend. Such enhancement in the properties of the TN nanocomposites could be attributed to the homogeneous dispersion, strong filler–blend interfacial interaction, and synergistic effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43470. 相似文献
80.
Jayeeta Chattopadhyay Tara Sankar Pathak Daewon Pak Rohit Srivastava 《Korean Journal of Chemical Engineering》2016,33(5):1514-1529
Metal micro-/nano hollow spheres have been widely applied in numerous fields during the last decade. This review will only focus on the synthetic strategies to synthesize hollow spherical structures in the enhancement of their electrocatalytic activity, especially the metal hollow spherical materials. We present a comprehensive overview of synthetic strategies for metal hollow spherical structures which have been approached specifically in electrochemical reactions. These synthetic methods are mainly categorized as hard templates, soft templates, sacrificial templates and without templates. The review further includes electrocatalytic approaches of hollow spherical metals in different electrochemical processes, especially the methanol electro-oxidation reaction for methanol fuel cell application and hydrogen and oxygen evolution reactions in water electrolyzer, as metal hollow spherical materials are especially applied in these specific reactions. 相似文献