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   334篇
  免费   17篇
电工技术   1篇
化学工业   89篇
金属工艺   1篇
机械仪表   6篇
建筑科学   18篇
能源动力   13篇
轻工业   118篇
水利工程   1篇
无线电   6篇
一般工业技术   31篇
冶金工业   9篇
自动化技术   58篇
  2023年   3篇
  2022年   17篇
  2021年   11篇
  2020年   7篇
  2019年   9篇
  2018年   6篇
  2017年   12篇
  2016年   8篇
  2015年   10篇
  2014年   19篇
  2013年   22篇
  2012年   18篇
  2011年   31篇
  2010年   21篇
  2009年   19篇
  2008年   36篇
  2007年   22篇
  2006年   15篇
  2005年   14篇
  2004年   10篇
  2003年   11篇
  2002年   6篇
  2001年   4篇
  2000年   2篇
  1999年   3篇
  1998年   5篇
  1996年   1篇
  1995年   1篇
  1992年   1篇
  1991年   1篇
  1989年   2篇
  1985年   1篇
  1984年   1篇
  1976年   1篇
  1968年   1篇
排序方式: 共有351条查询结果,搜索用时 31 毫秒
81.
BACKGROUND: Specific sugar contents are well known for contributing to a range of quality traits of fresh fruits such as flavour, texture and health properties. Peaches and nectarines of 205 genotypes from 14 different breeding progenies cultivated under Mediterranean conditions were evaluated by high‐performance liquid chromatography for their content of these sugar traits. RESULTS: A high contribution of cross to the phenotypic variance of all evaluated fruit quality traits was found. There were significant differences in mean sugar concentrations between peach and nectarine, yellow‐ and white‐fleshed or freestone and clingstone genotypes. Pre‐selected genotypes from the original breeding programme showed enhanced soluble solid content (SSC), total sugar and sucrose contents. A significant effect of year was found for SSC, sucrose and glucose contents, whereas no effect was found for fructose and sorbitol contents. Individual sugar contents correlated significantly with each other and with other fruit quality traits. CONCLUSION: A significant effect of cross, year and qualitative traits on the sugar profile of peaches and nectarines was found. Moreover, the differences shown in sugar traits between the breeding population and the pre‐selected genotypes indicated the importance of sugar profile in the global quality of peaches and nectarines. Copyright © 2009 Society of Chemical Industry  相似文献   
82.
Compression of CO2 is an essential process in the development of carbon capture and storage (CCS) technologies. In spite of power requirements for CO2 compression could be as much as 100 kWe per tonne CO2, the minimization of energy requirements has received little attention in the literature. Although intercooling compression reduces power requirements, it introduces important cooling necessities that could be minimized.The aim of this paper is the integration of intercooling compression into the low-pressure part of a steam cycle to take advantage of the intercooling heat and analyse the energetic and economical results under different assumptions. Simulation and optimization have been performed in order to evaluate the intercooling configuration, energy requirements and the most cost-effective integration. Results have shown reduction in compression power requirement around 40% and reduction of the incremental COE around 23%. Proposed integration could be used to increase the efficiency of CO2 capture processes and, therefore, to reduce the CO2 capture cost.  相似文献   
83.
Understanding pair-wise activities is an essential step towards studying complex group and crowd behaviors in video. However, such research is often hampered by a lack of datasets that concentrate specifically on Atomic Pair Actions; [Here, we distinguish between the atomic motion of individual objects and the atomic motion of pairs of objects. The term action in Atomic Pair Action means an atomic interaction movement of two objects in video; a pair activity, then, is composed of multiple actions by a pair or multiple pairs of interacting objects ( and ). Please see Section 1 for details.] in addition, the general dearth in computer vision of a standardized, structured approach for reproducing and analyzing the efficacy of different models limits the ability to compare different approaches. In this paper, we introduce the ISI Atomic Pair Actions dataset, a set of 90 videos that concentrate on the Atomic Pair Actions of objects in video, namely converging, diverging, and moving in parallel. We further incorporate a structured, end-to-end analysis methodology, based on workflows, to easily and automatically allow for standardized testing of state-of-the-art models, as well as inter-operability of varied codebases and incorporation of novel models. We demonstrate the efficacy of our structured framework by testing several models on the new dataset. In addition, we make the full dataset (the videos, along with their associated tracks and ground truth, and the exported workflows) publicly available to the research community for free use and extension at <http://research.sethi.org/ricky/datasets/>.  相似文献   
84.
The emission of trace metal pollutants by industry and transport takes place on a scale large enough to alter atmospheric chemistry and results in measurable differences between the urban background of inhalable particulate matter (PM) in different towns. This is particularly well demonstrated by the technogenic release into the atmosphere of V, Ni, and lanthanoid elements. We compare PM concentrations of these metals in large datasets from five industrial towns in Spain variously influenced by emissions from refinery, power station, shipping, stainless steel, ceramic tiles and brick-making. Increased La/Ce values in urban background inhalable PM, due to La-contamination from refineries and their residual products (fuel oils and petcoke), contrast with Ce-rich emissions from the ceramic related industry, and clearly demonstrate the value of this ratio as a sensitive and reliable tracer for many point source emissions. Similarly, anomalously high V/Ni values (> 4) can detect the influence of nearby high-V petcoke and fuel oil combustion, although the use of this ratio in urban background PM is limited by overlapping values in natural and anthropogenic materials. Geochemical characterisation of urban background PM is a valuable compliment to the physical monitoring of aerosols widely employed in urban areas, especially given the relevance of trace metal inhalation to urban health issues.  相似文献   
85.
This study presents an Exploratory Environmental Impact Assessment (EEIA) of the manufacturing process of a Polymer Electrolyte Membrane (PEM) fuel cell mounted in a cargobike, a three-wheel assisted-pedalling vehicle that is equipped to carry small loads, from a Life Cycle Assessment (LCA) approach. Results show that metals (both their production and processing) are the main contributors to the global warming and fossil energy use impact categories. Impact of platinum is considerable in acidification impact category, due to the large emissions of sulphur oxides produced during the extraction of the material. If recycled platinum is considered, a decrease of 20% could be achieved in this impact category.  相似文献   
86.
Seaweed waste (SWW) is a residue or by‐product from the filtration step of the agar extraction process, and it has been explored as an inexpensive and effective filler for incorporation by melt blending into a poly(lactic acid) (PLA) matrix. PLA‐SWW biocomposites were manufactured with various contents of SWW (0, 5, 10, 15, and 20 wt %) using a sheet extrusion process. PLA was functionalized with maleic anhydride (MAH) by reactive extrusion using dicumyl peroxide (DCP) as an initiator, and it was extruded using 0, 5, and 20 wt %. SWW content. The mechanical, thermal, structural, and morphological properties of the processed biocomposites were investigated. Regarding the mechanical behavior, a slight increase in the tensile modulus was observed at low SWW content. The thermal properties indicated that the rigid amorphous phase content was enhanced in the biocomposites. This work suggests that SWW can be used as filler to develop environmental friendly biocomposites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42320.  相似文献   
87.
The influence of seven plum rootstocks (Adesoto, Monpol, Montizo, Puebla de Soto 67 AD, PM 105 AD, St. Julien GF 655/2 and Constantí 1) on individual and total sugars, as well as on antioxidant content in fruit flesh of “Catherine” peaches, was evaluated for three years. Agronomical and basic fruit quality parameters were also determined. At twelve years after budding, significant differences were found between rootstocks for the different agronomic and fruit quality traits evaluated. The Pollizo plum rootstocks Adesoto and PM 105 AD seem to induce higher sweetness to peach fruits, based on soluble solids content, individual (sucrose, fructose and sorbitol) and total sugars. A clear tendency was also observed with the rootstock Adesoto, inducing the highest content of phenolics, flavonoids, vitamin C and relative antioxidant capacity (RAC). Thus, the results of this study demonstrate the significant effect of rootstock on the sugar profile and phytochemical characteristics of peach fruits. In addition, this work shows the importance of the sugar profile, because specific sugars play an important role in peach flavour quality, as well as the studied phytochemical compounds when looking for high quality peaches with enhanced health properties.  相似文献   
88.
To test whether a retinal or cortical mechanism sums contributions from two adapting fields to chromatic discrimination, L/M discrimination was measured with a test annulus surrounded by an inner circular field and an outer rectangular field. A retinal summation mechanism predicted that the discrimination pattern would not change with a change in the fixation location. Therefore, the fixation was set either in the inner or the outer field in two experiments. When one of the adapting fields was "red" and the other was "green," the adapting field where the observer fixated always had a stronger influence on chromatic discrimination. However, when one adapting field was "white" and the other was red or green, the white field always weighted more heavily than the other adapting field in determining discrimination thresholds, whether the white field or the fixation was in the inner or outer adapting field. These results suggest that a cortical mechanism determines the relative contributions from different adapting fields.  相似文献   
89.
A new formulation of dry fermented sausage, including ingredients that improve the nutritional and health benefits of this type of product is presented. Se yeast (2 g/kg), iodized salt (26 g/kg), linseed:algae (3:2) emulsion (62.5 g/kg), and lyophilized water extract of Melissa officinalis L. as a source of natural antioxidants (686 mg/kg), yielded dry fermented sausages with technological and sensory properties similar to traditional ones.  相似文献   
90.
BACKGROUND: ‘Diffuse skin browning’ (DSB) is a physiological disorder that affects Golden Delicious apples treated with 1‐methylcyclopropene (1‐MCP). Although a very high incidence is found, very little is known about the etiology of this disorder. This study aims to provide an understanding of the causes of this disorder and prevent it. RESULTS: A very high incidence of DSB was found in 1‐MCP‐treated apples independent of the location of the orchard. Similar to superficial scald, harvest maturity determines the DSB incidence, with the more mature fruit being less sensitive. The 1‐MCP dose (156 nL L?1 or 625 nL L?1) and the temperature at which the 1‐MCP treatment was applied (0.5 or 20 °C) did not affect the incidence of DSB. Diphenylamine (DPA) treatment did not prevent DSB, contrary to superficial scald. Additionally, controlled atmosphere storage only partially reduced the incidence of DSB, whereas progressive cooling strategies completely inhibited DSB occurrence. A direct correlation was found between the sensitivity of the Golden Delicious clone to russeting and its sensitivity to develop DSB during storage. CONCLUSION: Our results indicated that DSB and superficial scald are two different disorders involving different oxidative processes. DSB can be prevented by progressive cooling and selection of russeting‐resistant clones. Copyright © 2010 Society of Chemical Industry  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