首页 | 官方网站   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   261篇
  免费   19篇
工业技术   280篇
  2023年   1篇
  2021年   11篇
  2020年   11篇
  2019年   4篇
  2018年   7篇
  2017年   11篇
  2016年   11篇
  2015年   9篇
  2014年   5篇
  2013年   16篇
  2012年   16篇
  2011年   25篇
  2010年   16篇
  2009年   16篇
  2008年   6篇
  2007年   17篇
  2006年   15篇
  2005年   6篇
  2004年   7篇
  2003年   6篇
  2002年   7篇
  2001年   1篇
  2000年   6篇
  1999年   4篇
  1998年   7篇
  1997年   5篇
  1996年   7篇
  1995年   3篇
  1994年   2篇
  1993年   3篇
  1992年   2篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1976年   2篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1970年   1篇
  1968年   1篇
排序方式: 共有280条查询结果,搜索用时 15 毫秒
1.
2.
Species distribution models have recently become important tools in ecological research. Prediction of suitable habitats for threatened and endangered species is essential for the conservation and management of their native habitats. A landscape scale approach is relevant for biodiversity conservation since landscape planning and management are generally conducted at wide spatial scales, focusing on areas with complex landscape configuration as a consequence of human activities. The aims of this study were to test a maximum entropy approach (Maxent) to the development of a niche-based model for species of conservation interest and to relate this model to landscape structure metrics. The results obtained here showed a good predictive power of Maxent for the three target species and highlighted the importance of landscape structure analysis for the detection of patterns of habitat suitability. Moreover, this work stressed that combining classical environmental information with landscape structure in analysing habitat suitability for species of conservation interest may be used to guide conservation efforts and landscape management practices.  相似文献   
3.
We consider the standard model of spatial Cournot competition and show that for dispersion equilibria to exist, (a) a necessary condition is that the distribution be not unimodal, and (b) a sufficient condition is that the distribution be convex with a unique antimode and that asymmetry is not too strong.  相似文献   
4.
5.
The main goal of this paper is to design a compensator able to restore the nominal behavior of a planar system, which is rendered chaotic by an unmeasurable sinusoidal disturbance input. To reach such a goal, some instruments, taken from algebraic geometry, are used to estimate the unmeasurable disturbance from the time derivatives of the output of the system and of the control input. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
6.
Over the last 80 years, malting and brewing has evolved through increased scientific understanding, driven by numerous factors including efficiency improvement, cost reduction, quality enhancement, risk minimisation, brand marketing and image enhancement. The aim of this work was to review the historical trends in global brewing research in order to identify current opportunities and emerging trends, as well as uncover future key drivers. A bibliometric analysis was performed with English language peer reviewed literature from the Scopus database together with mapping using the VOSviewer clustering software. The bibliometric results were structured to identify which affiliations, authors, and journals have been involved in brewing research, as well as the average number of citations per paper. The bibliometric mapping yielded ‘research term maps’, where the words occurring more frequently in the research papers were grouped in coloured clusters by area of interest, and their relationships indicated. The year maps revealed which average terms tended to emerge in chronological order. The estimated average citation number per paper was about nine. Countries, including Spain, Czech Republic, Italy and Belgium displayed higher average citation scores than the world average. In the period 1940-79, brewing publications were mainly process oriented whereas between 2008-18, there was a shift in focus to the consumer (health and social responsibility) and to environmental sustainability. © 2020 The Institute of Brewing & Distilling  相似文献   
7.
8.
9.
10.
BACKGROUND: Three new artichoke seed‐propagated hybrids (Tempo, Opal and Madrigal) were compared with two standard cultivated varietal types [Catanese and Violet du Provence (VP)] in terms of head morphology, processing performance, nutritional or technological qualitative traits, in order to define their best use. RESULTS: Compared to the other genotypes, Opal and Madrigal had more rounded, heavier, larger heads, higher processing yield (>400 g of heart kg?1 raw head) and lower total phenol (TP) content (2.4 g of gallic acid equivalents kg?1 FW). VP gave a higher processing yield than Catanese and showed the highest TP content (6.5 g kg?1 FW). Tempo hearts were more similar to those of VP in biometrical and chemical terms (P, Na, K, Ca); they had the highest dry matter content (163 g kg?1 FW) and the waste left after peeling had the highest TP content. CONCLUSIONS: Hybrid artichokes, especially Opal and Madrigal, appear more suitable for the processing industry and also for fresh‐cut production due to their highest processing yield and lowest total phenol content. Because of its high total phenol content, Tempo waste represents a possible source of natural antioxidant in the pharmaceutical field and in the food industry (as a food additive). 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-23

京公网安备 11010802026262号