全文获取类型
收费全文 | 1421篇 |
免费 | 56篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 14篇 |
综合类 | 1篇 |
化学工业 | 382篇 |
金属工艺 | 51篇 |
机械仪表 | 29篇 |
建筑科学 | 64篇 |
矿业工程 | 1篇 |
能源动力 | 52篇 |
轻工业 | 171篇 |
水利工程 | 5篇 |
无线电 | 154篇 |
一般工业技术 | 288篇 |
冶金工业 | 56篇 |
原子能技术 | 10篇 |
自动化技术 | 201篇 |
出版年
2024年 | 2篇 |
2023年 | 10篇 |
2022年 | 30篇 |
2021年 | 52篇 |
2020年 | 25篇 |
2019年 | 26篇 |
2018年 | 26篇 |
2017年 | 22篇 |
2016年 | 32篇 |
2015年 | 27篇 |
2014年 | 52篇 |
2013年 | 109篇 |
2012年 | 81篇 |
2011年 | 132篇 |
2010年 | 97篇 |
2009年 | 83篇 |
2008年 | 84篇 |
2007年 | 63篇 |
2006年 | 66篇 |
2005年 | 49篇 |
2004年 | 38篇 |
2003年 | 41篇 |
2002年 | 38篇 |
2001年 | 20篇 |
2000年 | 19篇 |
1999年 | 22篇 |
1998年 | 14篇 |
1997年 | 32篇 |
1996年 | 15篇 |
1995年 | 22篇 |
1994年 | 15篇 |
1993年 | 12篇 |
1992年 | 10篇 |
1991年 | 13篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 13篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
排序方式: 共有1479条查询结果,搜索用时 15 毫秒
141.
Vincent Darras Sébastien Peralta Sylvie Boileau Dominique Teyssié Odile Fichet 《Polymer International》2010,59(6):743-748
Fluorinated polyacrylates are highly hydrophobic and oleophobic. However, their poor mechanical properties prevent their development in many applications. Combination of a fluorinated polyacrylate network with a rigid cellulose acetate butyrate (CAB) network in an interpenetrating polymer network (IPN) architecture is an effective method for improving the mechanical properties of fluorinated polyacrylates. IPNs combining poly(3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl acrylate) (polyAcRf6) with CAB were prepared according to an in situ polymerization/crosslinking synthesis. CAB was crosslinked by addition between unmodified hydroxyl groups and the isocyanate of a pluri‐isocyanate crosslinker. The fluorinated network was obtained through free‐radical copolymerization of 3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl acrylate with poly(ethylene glycol dimethacrylate). The rates of formation of both networks were followed using Fourier transform infrared spectroscopy. Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) of IPNs show a single glass transition temperature and a single mechanical relaxation temperature, which are characteristic of a high degree of interpenetration between the partner networks. The mechanical properties of IPNs are greatly improved compared with those of the single fluorinated network. CAB/polyAcRf6 IPNs were prepared, and characterized using DSC and DMTA as well as contact angle measurements for their surface properties. As hoped, the mechanical properties of such materials are much improved compared with those of the fluorinated partner alone. Copyright © 2010 Society of Chemical Industry 相似文献
142.
Christel Le Bon Taco Nicolai & Dominique Durand 《International Journal of Food Science & Technology》1999,34(5-6):451-465
Summary The aggregation of the globular protein β-lactoglobulin after heat-denaturation was studied in aqueous solution at pH 7 using static and dynamic light scattering. The structure of the aggregates is self-similar with fractal dimension 2.0. Size exclusion chromatography and dynamic light scattering measurements show that the aggregates have a broad size distribution. Initially clusters of about 85 proteins and 15 nm radius are formed which are the elementary units of the larger fractal aggregates. At low ionic strength the formation of the larger aggregates is impeded by electrostatic interactions.
The structure of the aggregates is independent of the concentration and the temperature. The rate of aggregation has an Arrhenius temperature dependence with an activation energy of about 350 kJ/mol weakly dependent on the concentration. The apparent reaction order of the aggregation is 1.5. In the mixture both variants A and B have the same aggregation rate. The gel time increases with decreasing concentration and diverges at about 0.7g L−1 . At lower concentration the aggregate growth stagnates when all protein has aggregated. 相似文献
The structure of the aggregates is independent of the concentration and the temperature. The rate of aggregation has an Arrhenius temperature dependence with an activation energy of about 350 kJ/mol weakly dependent on the concentration. The apparent reaction order of the aggregation is 1.5. In the mixture both variants A and B have the same aggregation rate. The gel time increases with decreasing concentration and diverges at about 0.7g L
143.
The main aim of this study is to characterize the effect of some commercial detergents on whey proteins in order to select an efficient detergent to clean inorganic membranes fouled during the process of whey proteins fractionation. The influence of such variables such as time, pH, temperature, type and detergent concentration on the rate of protein hydrolysis has been established. Also, the nature and size of produced peptides have been determined. The most efficient values of cleaning parameters have been obtained by using the enzymatic detergent P3-Ultrasil 62. 相似文献
144.
Manickam Minakshi Pritam Singh Dominique Appadoo Danielle E. Martin 《Electrochimica acta》2011,(11):A86
LiNiPO4 belongs to a family of olivine type compounds, with members LiMPO4 where M = Fe, Mn, Co or Ni are transition metals. The lithium nickel phosphate was prepared and characterized in order to evaluate a new potential cathode material for our ongoing research in aqueous rechargeable batteries. Annealing the final product is critical in obtaining the stoichiometric LiNiPO4 pure phase; conventional cooling to a room temperature leads to an indication of Li3PO4 and NiO secondary phases as impurities. The synchrotron infrared radiation (SR-IR) as a source for IR spectroscopy pins down the differences in the chemical bonding for annealed and conventional cooled LiNiPO4 samples. The cyclic voltammetric and galvanostatic studies showed annealed LiNiPO4 is electrochemically active from which lithium ions can be de-intercalated during oxidation process leading to an amorphous NiPO4 and a minor product of nickel(II) hydroxide (β-NiOOH). During subsequent reduction, lithium ions are not fully intercalated, however, the structure is reversible and adequate for multiple cycles. The high potential in LiNiPO4 looks to be very attractive in terms of high energy density, given the efficiency is improved. 相似文献
145.
The paper seeks to quantify the effect of urban politics on the microclimate of the city of Nantes (France), in particular those initiated by the sanitarians in the mid-19th century to find a remedy for the insalubrity that had been developing with urban densification since the late 17th century. Intensive historical research was first carried out in order to define and date the major transformations undergone by the city, its structure (densification, then widening of the streets, filling of water courses), the lifestyle habits (heating) or the building practices (appearance of stone and paving, higher buildings, insulation). This led to the definition of 5 characteristic states of the city, in 1680, 1756, 1835, 1880 and 1945. 相似文献
146.
Nabil Mameri Farid Halet Madani Drouiche Hocine Grib Hakim Lounici Djamila Belhocine Andr Pauss Dominique Piron 《加拿大化工杂志》2000,78(3):590-595
Olive oil production requires important quantities of washing water containing low oil concentrations, but classical processes used to recover or to eliminate this oil are ineffective. This study presents a membrane technique to treat olive oil mill washing water using different commercial ultrafiltration membranes: one organic (PCI) and two ceramic (Ceraver) membranes. The influence of the hydrodynamic parameters (transmembrane pressure and flow rate) and the cut‐off membranes on the efficiency of the ultrafiltration process was evaluated, and it was shown the organic PCI membrane could reduce pollution due to organic matter by decreasing the value of the Chemical oxygen demand by about 90%. Moreover, the nature of the ultrafine pore membrane appeared to be an important parameter which may strongly increase or decrease the capacity of the membrane. The membrane cut‐off did not have a strong influence on the performance of the process but if the membrane pores were too large the stability of the dynamically formed membrane decreased at transmembrane pressures greater than 0.2 MPa. 相似文献
147.
The representation within which attention operates was investigated in 3 experiments. The task was similar to that of R. Egly, J. Driver, and R. D. Rafal (1994). Participants had to detect the presence of a target at 1 of 4 ends of 2 shapes, differing in color and form. A precue appeared at 1 of the 4 possible corners. The 2 shapes occupied either the same or different locations in the cuing and target displays. The results showed that the cued object location was attended whether or not space was task relevant, whereas the cued object features (color and form) were attended only when these were task relevant. Moreover, when object file continuity was maintained through continuous movement, attention was found to follow the cued object file as it moved while also accruing to the cued location. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
148.
Dominique S. Tews 《Microscopy research and technique》2001,55(3):181-186
Nitric oxide (NO) is a short-living free molecule synthesized by three different isoforms of nitric oxide synthases (NOS)—neuronal NOS, endothelial NOS, and inducible NOS—associated with neuromuscular transmission, muscle contractility, mitochondrial respiration, and carbohydrate metabolism in skeletal muscle. Neuronal NOS is constitutively expressed at the muscle fiber sarcolemma linked to the dystrophin-glycoprotein complex and concentrated at the neuromuscular endplate. There is increasing evidence that altered expression of neuronal NOS plays a role in muscle fiber damage in neuromuscular diseases such as dystrophinopathies and denervating disorders. Although there have been some previous conflicting results on the neuronal NOS expression pattern in denervated muscle fibers, it is now well established that denervation is associated with a down-regulation and disappearance of sarcolemmal neuronal NOS at synaptic/extrasynaptic or both sites. As NO has been shown to induce collapse and growth arrest on neuronal growth cones, down-regulation of sarcolemmal neuronal NOS may contribute to axonal regeneration and attraction to muscle fibers aiming at the formation of new motor endplates providing reinnervation and reconstitution of NOS expression. As NO serves as a retrograde messenger, it may trigger structural downstream events responsible for neuromuscular synaptogenesis and preventing polyneural innervation. Nevertheless, decreased NO production in denervation reduces the cytoprotective scavenger function of NO for superoxide anions promoting oxidative stress that is likely to be involved in muscle fiber damage and death. However, the multifaced role of NOS and NO under physiological and pathological conditions remains poorly understood on the basis of the current knowledge. Microsc. Res. Tech. 55:181–186, 2001. © 2001 Wiley-Liss, Inc. 相似文献
149.
This paper presents the utilisation of planar millimeter wavelength whispering gallery dielectric resonators modes for the realization of directional filters and for application to power combination. The different advantages of these resonator modes allow their utilisation in the millimeter wavelength range. The electrical study based on the ring resonator theory permits to predict the theoretical responses of several circuits realised. Finally, experimental results obtained from power combiners in W band will be presented. 相似文献
150.
Muriel J. Wagner Michel Loubat Alain Sommier Dominique Le Ray Guylaine Collewet Bertrand Broyart Honoré Quintard Armel Davenel Gilles Trystram & Tiphaine Lucas 《International Journal of Food Science & Technology》2008,43(6):1129-1139
An oven dedicated to a magnetic resonance imager (MRI) was designed and constructed for continuous monitoring of the entire baking process. The general aim was to test whether response variables conventionally measured on bread loaves, such as temperature, density, and water loss, were consistent with those reported for similar products baked in classical convection ovens. MRI images acquired during baking are presented and discussed, emphasising the need to develop quantitative MRI methods allowing conversion of the MRI signal into one variable of interest, such as local density or local water content. 相似文献