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   156篇
  免费   31篇
化学工业   36篇
建筑科学   6篇
能源动力   1篇
轻工业   92篇
石油天然气   1篇
无线电   8篇
一般工业技术   20篇
冶金工业   8篇
自动化技术   15篇
  2023年   5篇
  2022年   1篇
  2021年   3篇
  2020年   1篇
  2019年   3篇
  2018年   7篇
  2017年   13篇
  2016年   11篇
  2015年   7篇
  2014年   13篇
  2013年   16篇
  2012年   14篇
  2011年   8篇
  2010年   13篇
  2009年   4篇
  2008年   12篇
  2007年   10篇
  2006年   5篇
  2005年   4篇
  2004年   6篇
  2003年   8篇
  2002年   2篇
  1999年   3篇
  1998年   3篇
  1997年   6篇
  1996年   3篇
  1995年   1篇
  1994年   3篇
  1985年   1篇
  1984年   1篇
排序方式: 共有187条查询结果,搜索用时 125 毫秒
1.
An evaluation of the Spanish CSIC performance in Biotechnology, as compared with those of the French CNRS and the Italian CNR, has been carried out to determine the balance between the generation of scientific knowledge and the transfer of technology. This study shows a high scientific productivity mostly in journals with moderate impact factor, a low generation of patents and an insufficient transfer of knowledge to the Spanish companies. Other indicators confirm the existence of competitive human resources in biotechnological research producing scientific knowledge of interest for the development of patents and that cooperates successfully at European level.  相似文献   
2.
3.
Humanitarian Non-Governmental Organisations (NGOs) play a growing role in the response to natural disasters, but despite being largely demanded, there is no available decision support system (DSS) specifically designed to address their problem. In this paper we present a decision support system (DSS) to aid those Humanitarian NGOs concerned with the response to natural disasters. Such a DSS has been designed avoiding sophisticated methodologies that may exceed the infrastructural requirements and constraints of emergency management by NGOs. A data-based, two-level knowledge methodology which allows damage assessment of multiple disaster scenarios is presented in order to address that problem. Validation results show viability of our approach.  相似文献   
4.
5.
The use of numerical models in physical oceanography, with the aim of reproducing and predicting water movements, is a common practice, especially for coastal areas. Nevertheless, results will be accurate only if the assumptions are appropriate and include all significant characteristics of the domain under modeling. Two-dimensional models are often used for shallow-water areas, but the implicit assumptions of conservation of a characteristic vertical profile for the horizontal velocities all over the domain and negligible vertical circulation must be exhaustively checked. Here a case is presented in which two-dimensionality would have led to inaccurate results, as the analysis of the field data showed a three-layer behavior. This case concerns the eastern coast of Gran Canaria island (Canary Islands) and illustrates how mathematical models will describe the phenomena they try to represent correctly only if all assumptions are right.  相似文献   
6.
The competition between α, β, and γ polymorphs has been studied in several random copolymers and terpolymers of propylene, by performing X‐ray diffraction and differential scanning calorimetry experiments. Formation of β‐crystals, achieved by the addition of a β‐nucleating agent, was found to be highly dependent on comonomer type and crystallization conditions. Additionally, the mechanical properties have been evaluated from stress‐strain, microhardness and dynamic‐mechanical thermal analyses. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers  相似文献   
7.
The numerical model presented simulates two-dimensional hydrodynamic conditions in order to predict both components of the average velocity, vertically integrated, as well as the free surface elevation of the sea in coastal waters. The equations supporting the model are the well-known shallow-water equations, or quasi-static equations. In the classical theory for long waves in shallow water, the vertical accelerations of the fluid particles are neglected because these accelerations are very small with respect to gravity. In the same manner, vertical velocities may be neglected when compared with the horizontal ones. Integration of the system of differential equations in partial derivatives has been performed by using a “leapfrog” finite-difference technique under explicit solving. The computer program was developed in FORTRAN 77. Results and their agreement with coastal configuration are shown for two applications of this model: the Delta del Ebro, on the Mediterranean coast of Spain, and the Ria de Pontevedra, on the Atlantic northwestern coast of Spain. Here attention is focused on the application to the Delta del Ebro area.  相似文献   
8.
A fast and reliable method for anthocyanin extraction and identification by HPLC‐DAD‐ESI/MS‐QTOF was used to analyse the anthocyanin composition of commercial red fruit juices (blackberry, redcurrant and pomegranate), purees (strawberry, cherry and raspberry) and concentrates (elderberry, blueberry and red grape). The anthocyanin profile of black carrot juice is also reported. The extraction and analysis method allowed us to detect and quantify a wide range of individual anthocyanins in a simple and rapid way. Pelargonidin‐3‐glucoside was detected in redcurrant for the first time and petunidin‐3‐galactoside quantified for the first time in blueberries. Considering the health benefits that have been associated with anthocyanin consumption, all these fruit and vegetables processed products could appear as a good source of this group of phytochemical compounds for their direct consumption or their use as ingredients for the design of new food product or food supplements.  相似文献   
9.
BACKGROUND: The aim of this study was to examine how different environmental factors (temperature, solar radiation, and vapour‐pressure deficit [VPD]) influenced nutritional quality and flavour of cherry tomato fruits (Solanum lycopersicum L. cv. Naomi) grown in two types of experimental Mediterranean greenhouses: parral (low technology) and multispan (high technology). RESULTS: Fruits were sampled three times during 3 years (2004, 2005 and 2006): at the beginning, middle and end of the fruit production period. Values for temperature, solar radiation, and VPD peaked in the third sampling in both greenhouses; values were higher in the parral‐type greenhouse, triggering abiotic stress. This stress reduced the accumulation of lycopene and essential elements, augmenting the phytonutrient content and the antioxidant capacity of tomatoes. During the third sampling, sugars were increased while organic acid content diminished, producing tomatoes with a sweeter‐milder flavour. The parral greenhouse produced tomatoes with higher phenolic compounds and ascorbic acid contents, together with a greater antioxidant capacity, without showing differences in flavour parameters. CONCLUSION: The higher phytonutrients content and antioxidant activity during the environmental stress, more pronounced in parral than multispan greenhouse, together with the sweeter‐milder flavour, conferred a notable nutritional benefit, which considerably improved the nutritional and organoleptic quality of these tomatoes. Copyright © 2010 Society of Chemical Industry  相似文献   
10.
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