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   406篇
  免费   9篇
  国内免费   1篇
电工技术   4篇
化学工业   91篇
金属工艺   1篇
机械仪表   9篇
建筑科学   14篇
能源动力   27篇
轻工业   37篇
石油天然气   1篇
无线电   45篇
一般工业技术   52篇
冶金工业   91篇
原子能技术   4篇
自动化技术   40篇
  2022年   2篇
  2021年   8篇
  2020年   2篇
  2019年   7篇
  2018年   6篇
  2017年   6篇
  2016年   8篇
  2015年   5篇
  2014年   10篇
  2013年   26篇
  2012年   11篇
  2011年   22篇
  2010年   7篇
  2009年   11篇
  2008年   17篇
  2007年   15篇
  2006年   19篇
  2005年   15篇
  2004年   10篇
  2003年   23篇
  2002年   14篇
  2001年   12篇
  2000年   7篇
  1999年   11篇
  1998年   33篇
  1997年   17篇
  1996年   6篇
  1995年   8篇
  1994年   10篇
  1993年   16篇
  1992年   5篇
  1989年   4篇
  1987年   3篇
  1985年   6篇
  1984年   2篇
  1983年   3篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1977年   2篇
  1976年   6篇
  1975年   1篇
  1974年   3篇
  1972年   2篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1966年   2篇
  1965年   1篇
排序方式: 共有416条查询结果,搜索用时 31 毫秒
11.
Nutritional research is currently entering the field of personalized nutrition, to a large extent driven by major technological breakthroughs in analytical sciences and biocomputing. An efficient launching of the personalized approach depends on the ability of researchers to comprehensively monitor and characterize interindividual variability in the activity of the human gastrointestinal tract. This information is currently not available in such a form. This review therefore aims at identifying and discussing published data, providing evidence on interindividual variability in the processing of the major nutrients, i.e., protein, fat, carbohydrates, vitamins, and minerals, along the gastrointestinal tract, including oral processing, intestinal digestion, and absorption. Although interindividual variability is not a primary endpoint of most studies identified, a significant number of publications provides a wealth of information on this topic for each category of nutrients. This knowledge remains fragmented, however, and understanding the clinical relevance of most of the interindividual responses to food ingestion described in this review remains unclear. In that regard, this review has identified a gap and sets the base for future research addressing the issue of the interindividual variability in the response of the human organism to the ingestion of foods.  相似文献   
12.
This study aimed to determine the kinetics of milk protein digestion and amino acid absorption after ingestion of four dairy matrices by six minipigs: unheated or heated skim milk and corresponding rennet gels. Digestive contents and plasma samples were collected over a 7 h-period after meal ingestion. Gelation of milk slowed down the outflow of the meal from the stomach and the subsequent absorption of amino acids, and decreased their bioavailability in peripheral blood. The gelled rennet matrices also led to low levels of milk proteins at the duodenum. Caseins and β-lactoglobulin, respectively, were sensitive and resistant to hydrolysis in the stomach with the unheated matrices, but showed similar digestion with the heated matrices, with a heat-induced susceptibility to hydrolysis for β-lactoglobulin. These results suggest a significant influence of the meal microstructure (resulting from heat treatment) and macrostructure (resulting from gelation process) on the different steps of milk proteins digestion.  相似文献   
13.
14.
Methods of separation and characterization of Cd in Zea Mays L. were studied by means of a radioisotopic technique based on injecting 109Cd into the plant. Two classic methods for fractionating plant material were compared. Cd was found to occur in all different cell components and a significant activity of Cd in the intracellular liquid is bound to proteins as indicated by chromatography on a molecular sieve. Cd fixed to cell walls exchanges entirely after selective solvent extraction with H2O, KNO3, HAc, HCl. Our results indicate Cd‐binding sites in stems.  相似文献   
15.
Several in-well aeration (IWA) technologies have been used since the early 1990s, but few field studies have been performed to evaluate the extent of water circulation around IWA systems. In this study, 27 discrete monitoring points (MPs) were installed at a gasoline-contaminated site to assess the efficacy of IWA. Pressure transducers and dissolved oxygen (DO) probes were sealed into the MPs, allowing them to be used to characterize subsurface changes in total head and DO with depth, distance and orientation from a central injection well. No change in DO or in hydrocarbon total mass or distribution occurred across the site during two trials (41 and 20 days) of the system. Water level fluctuations during the trials were similar in all MPs, and were due to seasonal water table changes and rainfall events. No circulation cell was established around the IWA well after 41 days of operation, and the impact of the well extended less than 90cm from it. Groundwater only circulated through the sand pack around the well. Little, if any, recharge occurred through the lower screen. Silt accumulated in the well, limiting its operation time, even with a fabric filter sock over the lower screen. Obviously, IWA was ineffective at this site, probably because the horizontal hydraulic conductivity (K(h)) of the soil opposite the lower screen was low (0.09cm per day) and because the distance between the two screens was short relative to the borehole radius. Long remediation times would likely make IWA unattractive at this or other sites where the K(h) of the soil is so low that the air injection rate would have to be low to prevent blowing the well dry.  相似文献   
16.
This article presents a novel application of grammatical inference techniques to the synthesis of behavior models of software systems. This synthesis is used for the elicitation of software requirements. This problem is formulated as a deterministic finite-state automaton induction problem from positive and negative scenarios provided by an end user of the software-to-be. A query-driven state merging (QSM) algorithm is proposed. It extends the Regular Positive and Negative Inference (RPNI) and blue-fringe algorithms by allowing membership queries to be submitted to the end user. State merging operations can be further constrained by some prior domain knowledge formulated as fluents, goals, domain properties, and models of external software components. The incorporation of domain knowledge both reduces the number of queries and guarantees that the induced model is consistent with such knowledge. The proposed techniques are implemented in the ISIS tool and practical evaluations on standard requirements engineering test cases and synthetic data illustrate the interest of this approach.  相似文献   
17.
A solid CoII complex with l-proline as ligand was synthesized and fully characterized using spectroscopic studies, magnetic data, and DFT calculations. Dioxygen scavenging properties were investigated by UV/Vis spectroscopy and oxymetry techniques. The Co-proline system presented very interesting properties in matter of oxygen absorption capacity both in solution and incorporated in a polymer matrix.  相似文献   
18.
We conclude, in this third part, the presentation of an algorithm for computing an exact and proper parameterization of the intersection of two quadrics. The coordinate functions of the parameterizations in projective space are polynomial, whenever it is possible. They are also near-optimal in the sense that the number of distinct square roots appearing in the coefficients of these functions is minimal except in a small number of cases (characterized by the real type of the intersection) where there may be an extra square root.  相似文献   
19.
Mesoporous single crystal (PSC) oxides have been reported as presenting higher electrochemical performances than bulk materials in lithium ion batteries operating via intercalation processes. Here, we extend this study to the electrochemical behaviour of mesoporous Cr2O3 versus Li+/Li0. We confirm that the Cr2O3 reacts towards Li through a conversion reaction mechanism leading, upon discharge, to the formation of large metallic chromium nanoparticles (10 nm); the latter are embedded into a Li2O matrix together with, in this specific case, a copious amount of polymeric materials coming from electrolyte degradation, surrounding the particles, and filling the pores. During the following charge, re-oxidation of the nanoparticles occurs with the formation of CrO1−x, with the main difference, as opposed to bulk Cr2O3 electrodes, being the preservation of the polymeric layer at the end of the charge. We believe the material mesoporosity, via capillary effects, to be at the origin of such a difference. These electrolyte degradation products are shown to help in maintaining the material mesoporosity for a great number of cycles; and interestingly they are not detrimental to the cell performance in terms of capacity retention while presenting great advantages in terms of charge transfer by reducing diffusion lengths, namely for Li+ ions. The positive attributes of mesoporous material-based electrodes noticed for insertion reactions can then be extended to conversion reaction electrodes as long as we can master their synthesis while controlling their mesoporosity through either soft or hard templating techniques.  相似文献   
20.
Studied the psychometric properties and the theoretical validity of the French translation of the Inventory of Personality Organization (IPO; O. F. Kernberg and J. F. Clarkin, 1995). The IPO was administered to 845 males and females from a Quebec university and from the general Quebec population. Separate exploratory and 1st-level confirmatory factor analyses were performed. The results indicate a good level of conformity between IPO items and the tridimensional primary constructs of O. F. Kernberg's theoretical model of personality organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  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