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   308篇
  免费   24篇
电工技术   2篇
化学工业   91篇
建筑科学   12篇
能源动力   9篇
轻工业   104篇
水利工程   4篇
石油天然气   2篇
无线电   12篇
一般工业技术   31篇
冶金工业   4篇
原子能技术   1篇
自动化技术   60篇
  2023年   1篇
  2022年   14篇
  2021年   18篇
  2020年   2篇
  2019年   6篇
  2018年   8篇
  2017年   9篇
  2016年   10篇
  2015年   12篇
  2014年   18篇
  2013年   26篇
  2012年   21篇
  2011年   33篇
  2010年   21篇
  2009年   30篇
  2008年   20篇
  2007年   14篇
  2006年   7篇
  2005年   11篇
  2004年   10篇
  2003年   15篇
  2002年   10篇
  2001年   1篇
  2000年   2篇
  1999年   1篇
  1998年   2篇
  1997年   3篇
  1995年   2篇
  1989年   1篇
  1986年   1篇
  1985年   3篇
排序方式: 共有332条查询结果,搜索用时 937 毫秒
61.
The gross composition, the main physicochemical parameters, the proteolytic changes and the characteristics of the fat throughout the manufacture process, and the sensorial characteristics of the final product, were studied in dry-cured lacón, a traditional dry-salted and ripened meat product made in the north-west of Spain from the fore leg of the pig following a similar technological process to that of dry-cured ham. The effect of the use of additives (glucose, sodium nitrite, sodium nitrate, sodium ascorbate and sodium citrate) was also studied.In comparison with other dry-cured meat products made from whole meat pieces, dry-cured lacón is characterised by the low moisture contents, the high pH values, and the low transformation of the pigments. The proteolytic and lipolytic processes throughout the manufacture of this product were not intense. Except for the total carbohydrate and nitrate contents, and the percentage of transformation of the pigments, which were significantly (P < 0.05) higher in the batches processed with additives, the use of additives did not influence the biochemical modifications that occur throughout the manufacture process of the dry-cured lacón. Regarding the sensorial characteristics, the use of additives seems to improve the colour and the odour of the final product.  相似文献   
62.
We propose a fast algorithm for evaluating the moments of Bingham distribution. The calculation is done by piecewise rational approximation, where interpolation and Gaussian integrals are utilized. Numerical tests show that the algorithm reaches the maximum absolute error less than \(5\times 10^{-8}\) remarkably faster than adaptive numerical quadrature. We apply the algorithm to a model for liquid crystals with the Bingham distribution to examine the defect patterns of rod-like molecules confined in a sphere, and find a different pattern from the Landau-de Gennes theory.  相似文献   
63.
The appearance of some laws that make the electronic signature (e‐signature) legally equivalent to the handwritten signature (under some circumstances) has favoured its use in different fields, such as e‐commerce and e‐government. In these fields, the e‐signatures associated to some documents have to remain valid over long periods of time. For these kinds of e‐signatures, Advanced Electronic Signature (AdES) forms have appeared. These forms specify the information to include along with the e‐signature so that it remains valid for a long time after its creation. Basically, this information comprises signers' certificates, a set of certificates up to a trust anchor, certificate validation responses, etc. These data can be gathered by using different Public Key Infrastructure‐compliant protocols. However, the support of different protocols is complex for clients. XML Key Management Specification (XKMS) appeared with the aim of simplifying the certificate management, but it only supports a simple validation mechanism that does not provide the information needed for long‐term validation. As a solution to this problem, we have extended XKMS by defining an advanced certificate validation service to support the obtaining of validation data needed for different scenarios, such as the building of AdES forms or validation data registries. This extension also defines the different components needed to support this kind of a service. Furthermore, the defined service has been implemented and incorporated into an e‐government infrastructure. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
64.
In this paper we present a model to predict Secchi depth in water bodies by means of an artificial neural network application onto eight bit microcontroller. Water turbidity data were collected by both a Secchi disk and a new patented device (named LUZEX) that uses commercial photodiodes with not monochromatic sensitive band as a basis to perform “in situ” measurements for sunlight extinction coefficients. In order to have a wide range of turbidity data three different water bodies were selected to do the measurements. The developed neural network model is able to relate well the data obtained by these methods and the obtained value for regression coefficient (R) is 0.998.Secchi depth measure is a reference method to determine turbidity in continental and coastal water bodies, especially in the Mediterranean Sea region, but sometimes there are particular cases that makes difficult the use of the Secchi disk (e.g. shallow water bodies), the authors propose LUZEX as a substitute for Secchi disk when it is difficult or impossible to use.  相似文献   
65.
Interaction between insect herbivores and host plants can be modulated by endogenous and exogenous compounds present in the source of food and might be successfully exploited in Colorado potato beetle (CPB) pest management. Feeding tests with CPB larvae reared on three solanaceous plants (potato, eggplant and tomato) resulted in variable larval growth rates and differential susceptibility to Bacillus thuringiensis Cry3Aa toxin as a function of the host plant. An inverse correlation with toxicity was observed in Cry3Aa proteolytic patterns generated by CPB midgut brush-border membrane vesicles (BBMV) from Solanaceae-fed larvae, being the toxin most extensively proteolyzed on potato, followed by eggplant and tomato. We found that CPB cysteine proteases intestains may interact with Cry3Aa toxin and, in CPB BBMV from larvae fed all three Solanaceae, the toxin was able to compete for the hydrolysis of a papain substrate. In response to treatment with the JA-dependent plant inducer Hexanoic acid (Hx), we showed that eggplant reduced OPDA basal levels and both, potato and eggplant induced JA-Ile. CPB larvae feeding on Hx-induced plants exhibited enhanced Cry3Aa toxicity, which correlated with altered papain activity. Results indicated host-mediated effects on B. thuringiensis efficacy against CPB that can be enhanced in combination with Hx plant induction.  相似文献   
66.
67.
68.
In the present work a study was made of the use of near infra-red spectroscopy (NIRS) technology with a remote reflectance fibre–optic probe for the analysis of hydroxyproline in cured pork sausages (salchichón and chorizo) and dry cured beef (cecina). The presence of the amino acid hydroxyproline was used as an analytical criterion to assess the amount of collagen from connective tissues versus lean meat (muscle). The fibre–optic probe was placed directly on the sample with no previous treatment or manipulation.The regression method employed was that of modified partial least squares (MPLS). The equation developed for a total of 80 samples (salchichón, chorizo and cecina) allowed the determination of the hydroxyproline content within a range of 0–0.74%. The multiple correlation coefficient (RSQ) and standard error of prediction corrected (SEP(C)) obtained were respectively 0.772 and 0.05%. The predicted values of hydroxyproline in unknown samples using NIRS technology and applying the fibre–optic probe directly on the sample without previous treatment were comparable to those obtained using the chemical method.  相似文献   
69.
BACKGROUND: Differences in instrumental measurements of colour and viscosity were analysed in six commercial samples of vanilla beverages, three of milk and three of soybean. Sensory differences between them were assessed and an analysis was made of whether the perceived differences had any influence on consumer preferences with respect to these attributes. RESULTS: The milk beverages were a stronger yellow in colour (45.05≤b*≤60.02) than the soybean beverages (18.46≤b*≤21.96). The flow of all samples was Newtonian, showing viscosity values in the range 4.34–7.92 mPa s. Significant differences in viscosity were detected between samples. Sensory results revealed that the vanilla milk samples were perceived as having a stronger yellow colour and being thicker than the vanilla soymilk samples. The majority of people surveyed (n = 142) preferred the samples that were deeper yellow in colour; moreover, the thickness of milk samples was significantly more acceptable than that of soymilk samples. CONCLUSION: The instrumental measurement of colour relates well to the perceived differences in the colour of these products and explains the differences in consumer preferences. However, the instrumental viscosity values do not relate well to the thickness perceived or to the differences in acceptability of the beverages. Copyright © 2007 Society of Chemical Industry  相似文献   
70.
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