首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   108篇
  免费   7篇
电工技术   1篇
综合类   1篇
化学工业   27篇
金属工艺   3篇
机械仪表   2篇
建筑科学   11篇
能源动力   3篇
轻工业   21篇
水利工程   2篇
石油天然气   1篇
无线电   6篇
一般工业技术   13篇
冶金工业   7篇
原子能技术   2篇
自动化技术   15篇
  2022年   2篇
  2021年   2篇
  2019年   3篇
  2018年   5篇
  2017年   3篇
  2016年   9篇
  2015年   2篇
  2014年   5篇
  2013年   8篇
  2012年   7篇
  2011年   6篇
  2010年   4篇
  2009年   7篇
  2008年   5篇
  2007年   4篇
  2006年   3篇
  2005年   5篇
  2004年   2篇
  2003年   5篇
  2002年   2篇
  2000年   3篇
  1999年   4篇
  1998年   5篇
  1997年   3篇
  1995年   1篇
  1993年   2篇
  1992年   1篇
  1990年   1篇
  1987年   2篇
  1985年   1篇
  1982年   1篇
  1979年   1篇
  1969年   1篇
排序方式: 共有115条查询结果,搜索用时 0 毫秒
101.
Extrusion cooking is commonly used in the production of snacks. In the present study, extrudates were prepared using barley flour alone and with the addition of either polydextrose (PD) or whey protein isolate (WPI) and both PD and WPI. Independent process variables were water content of the mass (17%, 20% and 23%), screw speed (200, 350 and 500 rpm) and temperature of section 6 and die (110, 130 and 150 °C). Expansion, hardness, water content, porosity and chemical composition of the extrudates were analysed. Highly porous and expanded snack products with high dietary fibre and protein contents were obtained from barley flour and WPI when water content of mass was 17%, screw speed 500 rpm and temperature of section 6 and die 130 °C. Barley flour alone or with PD resulted in hard and non‐expanded extrudates. Expansion of extrudates was statistically significantly increased with decreasing water content of the mass and increasing screw speed in all trials.  相似文献   
102.
The cardiac autonomic nervous system (cANS) regulates cardiac function by innervating cardiac tissue with axons, and cardiomyocytes (CMs) and neurons undergo comaturation during the heart innervation in embryogenesis. As cANS is essential for cardiac function, its dysfunctions might be fatal; therefore, cardiac innervation models for studying embryogenesis, cardiac diseases, and drug screening are needed. However, previously reported neuron-cardiomyocyte (CM) coculture chips lack studies of functional neuron–CM interactions with completely human-based cell models. Here, we present a novel completely human cell-based and electrophysiologically functional cardiac innervation on a chip in which a compartmentalized microfluidic device, a 3D3C chip, was used to coculture human induced pluripotent stem cell (hiPSC)-derived neurons and CMs. The 3D3C chip enabled the coculture of both cell types with their respective culture media in their own compartments while allowing the neuronal axons to traverse between the compartments via microtunnels connecting the compartments. Furthermore, the 3D3C chip allowed the use of diverse analysis methods, including immunocytochemistry, RT-qPCR and video microscopy. This system resembled the in vivo axon-mediated neuron–CM interaction. In this study, the evaluation of the CM beating response during chemical stimulation of neurons showed that hiPSC-neurons and hiPSC-CMs formed electrophysiologically functional axon-mediated interactions.  相似文献   
103.
This study investigated the influence of pH of adsorption medium and co-adsorptive metal cations for the adsorption of potassium (K+) and magnesium (Mg2+) ions onto poly (vinylidene fluoride) grafted poly(acrylic acid) (PAA-PVDF) membrane. At pH 4.8, the adsorption of potassium and magnesium was minimal, because of nearly non-dissociated carboxylic acid groups of PAA-chains, but adsorption increased with increasing ion concentration. The interaction of the studied cations between PVDF-PAA membranes increased considerably at pH 7.0 the dissociation of carboxylic acid groups of PAA. The addition of ionic substances (calcium (Ca2+) and sodium (Na+) to the adsorption medium reduced the adsorption of potassium and magnesium onto the membrane, because of co-adsorption. Divalent calcium reduced more effectively than univalent sodium the adsorption of potassium and magnesium onto the membrane. In conclusion, co-adsorbing ions reduced the adsorbed amount of potassium and magnesium ions due to binding competition. The percentual adsorbed values suggest that adsorption affinity of studied ions onto the PVDF-PAA membrane followed the order Na+ < K+ < Mg2+ < Ca2+. The effect of metal cations on drug adsorption from biological fluids needs research in the future, because e.g. PVDF-PAA membrane has been used in drug separation processes.  相似文献   
104.
The self-assembling behaviour of a four-arm amphiphilic star block copolymer, (PMMA73-b-PAA143)4, with poly(methyl methacrylate) inner blocks and poly(acrylic acid) outer blocks in ratio 1:2 (PMMA:PAA) has been investigated in aqueous solutions as a function of pH by dynamic light scattering and cryo-transmission electron microscopy. At low pH (pH ≤ 5) the amphiphile forms in the presence of salt both spherical and worm-like micellar aggregates that coexist in solution. At high pH (pH > 12) the solution contains mainly spherical micelles and a small number of larger aggregates that have ‘pearl-necklace’ structure, indicating the disintegration of the worm-like species. In addition to the experiments, computer simulations of the four-arm amphiphilic star block copolymer with the same ratio of the blocks as above were conducted using a coarse-grained model. The simulations predict the formation of the worm-like micellar aggregates at low pH and the spherical ones at high pH. The changes in the morphology of the aggregates are related to the higher degree of ionization of poly(acrylic acid) blocks at high pH and to the swelling of the corona of the micelles by the higher osmotic pressure due to trapped counterions.  相似文献   
105.
106.
Controlled psychoperceptual quality evaluation experiments are used to assess the excellence of produced audiovisual quality from fundamental signal processing algorithms to consumer services. When compromising produced quality for consumer services, used in dynamic and heterogeneous mobile contexts, the ecological validity of conventional quality evaluation methods can be questioned. The goal of this paper is to develop a method for evaluating the experienced multimedia quality in the context of use. We conducted three studies where the quality of mobile 2D and 3D television was assessed in three different field contexts, one simulated context and one controlled laboratory situation when audio-video compression and transmission parameters were varied. We propose a hybrid method for the design, data-collection and analysis of the experiments in the contexts of use. Its novelty is to complement conventional quantitative quality evaluation with concrete tools to identify factors that surround the assessment in the context. The methodological framework is part of our long-term aim to measure and understand the user-centered quality of experience.  相似文献   
107.
108.
    
Zusammenfassung Der Bericht gibt eine Übersicht über neuere finnische Flugwilduntersuchungen, die von Wildbiologen des Staatlichen Instituts für Wildforschung, Helsinki, gemacht worden sind. Diese Untersuchungen beziehen sich vor allem auf die Tetraoniden und Wasservögel. Die Zusammensetzung der Tetraonidenpopulation des Landes wurde mit zwei verschiedenen Methoden festgestellt. Erstens durch das Analysieren von Schwingenproben, die während der Jagdzeit gesammelt wurden (Helminen 1963), und zweitens mit Hilfe der im August durchgeführten direkten Besatzzählungen (Rajala 1966, 1967 und 1968). Außerdem wurden lokale Birk- und Auerwildpopulationen sowie deren Balzverhalten untersucht (Koivisto 1965,Pirkola undKoivisto 1968). Der Gegenstand der Wasservogeluntersuchungen war die Zusammensetzung der Meeresvögelbesätze, die im äußeren Archipel nisten, sowie deren Besatzschwankungen (Grenquist 1965 und 1966), das Brutverhalten der Schellente (Grenquist 1962 und 1963), ferner die Brutökologie und Populationszusammensetzung der Stockente (Pirkola 1967 und 1968). Bei den Ringel- und Hohltauben wurde die Dauer der Nistperiode in Südfinnland untersucht (Koivisto 1959 und 1962). Bezüglich der Greifvogel-Untersuchungen wird über die Nahrung des Steinadlers während der Horstzeit im finnischen Rentierzuchtgebiet berichtet (Sulkava undRajala 1966). Eine eigens gebildete Gruppe befaßt sich mit der Pestizidforschung, welche sich zunächst mit der Untersuchung von Federwild und Greifvögeln auf Quecksilbergehalt beschäfligt (Helminen 1966,Helminen et al. 1966 sowieHenriksson et al. 1966 a und b).
Summary This review introduces some of the recent studies on game birds in Finland, made by the staff of the State Game Research Institute, Helsinki. The studies center primarily on teraonids and sea-birds. The composition of the tetraonid populations in Finland has been investigated using two different methods, on one hand by analyzing the wing samples collected in hunting (Helminen 1963) and on the other hand from the bird census made in August (Rajala 1966, 1967 and 1968). In addition, some research has been made on the local populations and spring display behaviour of capercaillie and black grouse (Koivisto 1965,Pirkola andKoivisto 1968). The sea-bird studies have concentrated on the composition and abundance of sea-bird populations nesting in the outer archipelago areas (Grenquist 1965 and 1966), the nesting of the goldeneye (Grenquist 1962 and 1963) and the brood ecology and the population composition of the mallard (Pirkola 1967 and 1968). Among the pigeons a study was made on the length of the nesting period of wood pigeons and stock doves in Southern Finland (Koivisto 1959 and 1962). The research on birds of prey is represented by a study on the diet of the golden eagle during the nesting period in the Finnish reindeer husbandry area (Sulkava andRajala 1966). A special category is composed of biocide studies dealing with the occurrence of mercury in game birds and birds of prey (Helminen 1966,Helminen et al. 1966 andHenriksson et al. 1966a and b).

Résumé Cette revue présente les études récentes sur les oiseaux de gibier faites en Finlande par le personnel de l'Institut National de Recherche sur le Gibier, Helsinki. Les recherches furent d'abord centrées sur les Tétraonidés et les oiseaux de mer. La composition des populations de Tétraonidés en Finlande fut examiné par deux méthodes différentes, d'une part en analysant les ailes des oiseaux collectés lors de la chasse (Helminen 1963), et d'autre part d'après des recensements d'oiseaux pratiqués durant le mois a'Août (Rajala 1966, 1967 et 1968). De plus, des recherches ont été faites sur le comportement nuptial au printemps sur des populations locales de Grand Tétras et de Tétras Lyre (Koivisto 1965,Pirkola etKoivisto 1968). Les recherches sur les oiseaux de mer furent concentrées sur la composition et l'abondance des populations nichant dans l'archipel extérieur (Grenquist 1965 et 1966), la nidification du Garrot à oeil d'or (Grenquist 1962 et 1963), l'écologie de la reproduction et la composition des populations du Canard col-vert (Pirkola 1967 et 1968). Ont été également effectuées sur les Colombidés des recherches sur la duré de la période de nidification du Pigeon Ramier et du Pigeon Colombin dans le sud de la Finlande (Koivisto 1959 et 1962). La recherche sur les oiseaux de proie se manifeste par une étude du régime alimentaire de l'Aigle Royal durant la nidification, à l'intérieur de l'aire de distribution du Renne (Sulkava etRajala 1966). Enfin, un programme spécial de recherches sur les pesticides en relation avec la présence de mercure chez les oiseaux de gibier et les oiseaux de proie (Helminen 1966,Helminen et al. 1966 etHenriksson et al. 1966a et b).
  相似文献   
109.
Demolition of buildings is one fundamental, but little studied, factor in the dynamics of building stocks. This research study examines the characteristics and location of demolished buildings in Finland as well as motives behind the demolition decisions. A statistical and geographical analysis was performed on a dataset of all 50 818 buildings demolished in Finland between 2000 and 2012. In the Finnish context, the study shows that the amount of demolition, the size of the community, demographic development and construction activity are all interconnected. In general, the larger the community, the more it gains inhabitants and the more is built as well as demolished. The data confirm that removals from the building stock are a result of conscious deliberation. Non-residential buildings dominate the amount of demolished floor area. In addition, they are much larger and younger at the time of demolition than residential buildings, which consist primarily of detached houses. Demolitions are geographically concentrated: cities account for 76% of demolished floor area; and city cores for as much as 44%. Public policy needs to include demolition to reduce environmental impacts and improve resource efficiency.  相似文献   
110.
The objective of this study was to measure the concentrations of organotin compounds in the whole blood of Finnish male fishermen (n=133), their wives (n=94), and other family members (n=73), and to investigate their associations with background variables. The concentrations were generally low, less than the limit of quantification (LOQ) for the vast majority of compounds and samples. Of the organotin compounds (mono-, di-, and tributyltin, mono-, di-, and triphenyltin, and dioctyltin), only triphenyltin was detected in more than just a few samples (in 37 of 300 samples, LOQ=0.04 ng/ml). These were mainly the samples of fishermen (26/37) and their wives (10/37). For statistical analysis, concentrations of triphenyltin were divided into two categories, LOQ. Of the different background variables, age and fish consumption contributed the most to the triphenyltin concentrations. When age and fish consumption (g/day) were divided into three categories, odds ratios comparing the highest with the lowest category were 3.88 for age (95% CI 1.36-11.09) and 3.48 for fish consumption (1.36-8.94), respectively. Compared with females, males had an odds ratio of 1.51 of having the concentration of triphenyltin >LOQ (0.72-3.14). To the best of our knowledge, this study confirmed for the first time with human samples that fish consumption can be associated with triphenyltin concentration in whole blood.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号