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   699篇
  免费   34篇
电工技术   4篇
化学工业   277篇
金属工艺   9篇
机械仪表   13篇
建筑科学   15篇
能源动力   28篇
轻工业   83篇
水利工程   3篇
石油天然气   4篇
无线电   57篇
一般工业技术   93篇
冶金工业   17篇
原子能技术   3篇
自动化技术   127篇
  2023年   6篇
  2022年   38篇
  2021年   58篇
  2020年   30篇
  2019年   25篇
  2018年   27篇
  2017年   21篇
  2016年   36篇
  2015年   22篇
  2014年   39篇
  2013年   47篇
  2012年   49篇
  2011年   42篇
  2010年   38篇
  2009年   36篇
  2008年   25篇
  2007年   25篇
  2006年   18篇
  2005年   15篇
  2004年   10篇
  2003年   13篇
  2002年   11篇
  2001年   7篇
  2000年   4篇
  1999年   4篇
  1998年   7篇
  1997年   3篇
  1996年   4篇
  1995年   2篇
  1994年   3篇
  1993年   3篇
  1992年   4篇
  1991年   6篇
  1990年   2篇
  1989年   2篇
  1987年   5篇
  1986年   2篇
  1985年   7篇
  1984年   4篇
  1983年   4篇
  1982年   3篇
  1980年   4篇
  1979年   2篇
  1971年   3篇
  1961年   1篇
  1959年   1篇
  1939年   1篇
  1937年   1篇
  1933年   2篇
  1916年   2篇
排序方式: 共有733条查询结果,搜索用时 11 毫秒
681.
This article aims to achieve two goals: to show that probability is not the only way of dealing with uncertainty (and even more, that there are kinds of uncertainty which are for principled reasons not addressable with probabilistic means); and to provide evidence that logic-based methods can well support reasoning with uncertainty. For the latter claim, two paradigmatic examples are presented: logic programming with Kleene semantics for modelling reasoning from information in a discourse, to an interpretation of the state of affairs of the intended model, and a neural-symbolic implementation of input/output logic for dealing with uncertainty in dynamic normative contexts.  相似文献   
682.
683.
We describe the parallel full-f gyrokinetic particle-in-cell plasma simulation code ELMFIRE and the issue of solving an electrostatic potential from particle data distributed across several MPI (Message Passing Interface) processes. The potential is solved through a linear system with a strongly sparse matrix and ELMFIRE stores data of the estimated non-zero diagonals of the whole matrix in every MPI process. We present and compare several memory efficient structures for gathering the matrix data while keeping only a local part of the matrix in each process. We also demonstrate that these alternative structures improve scalability, thus enabling ELMFIRE to use more MPI processes and a finer time and space scale than before without sacrificing performance.  相似文献   
684.
685.
Skype is a Voice over IP (VoIP) Internet application that is gaining huge popularity in recent years. A key point to Skype popularity is its capability to dynamically adapt itself to operate behind firewalls or network proxies. A common way adopted by Skype to delude these network devices is to use port 80, normally expected to comprise HTTP traffic. In this paper, we propose metrics and investigate statistical tests intended to clearly distinguish Skype flows from HTTP traffic. We validate our study using real-world experimental datasets gathered at a commercial Internet Service Provider (ISP). Our experimental results suggest that the proposed methodology may be seen as a promising building block towards a system to detect general protocol anomalies in HTTP traffic.  相似文献   
686.
687.
688.
The oxidation of 1H-indene and 1,2-dihydronaphthalene with hydrogen peroxide in the presence of Mn(III) or Fe(III) substituted Keggin-type polyoxotungstates is described. The products obtained depend on the catalyst and reaction conditions. Ring cleavage was observed, affording dialdehydes under mild and environmentally friendly conditions. Other main products were the α-hydroxy-ketones. The resulting epoxides seem to be intermediates to other oxygenated products.  相似文献   
689.
Obesity and cardiovascular diseases are among the most worrying health problems worldwide. Dietary habits can be catalysts for the rise of these health issues in western countries. In this work, a meat product (pork patties) commonly elaborated with a high fraction of saturated fat is reformulated with an oleogel based on linseed oil (rich in polyunsaturated fatty acids). The oleogel is used for the partial replacement of the solid fat fraction present in pork patties (H‐25 for 25% and H‐75 for 75% of replacement). Incorporation of oleogels results in the modification of the fatty acid profile and in the significant decrease of the omega‐6/omega‐3 ratio. Results show that for both degrees of fat substitution, there are no differences between the patties produced with oleogel incorporation and the control, regarding textural parameters such as hardness, cohesiveness, and chewiness. Overall, samples with less amount of oleogel (H‐25) are well classified in the acceptance and preference tests, despite the clear preference among the sensorial panel toward the control samples. These results show the feasibility of introducing oleogels as a fat replacer in the manufacturing process of pork patties, though there is still work to be done regarding some of their sensorial attributes. Practical Applications: The purpose of this work is focused on the study of the properties of meat patties after the replacement of saturated fat with a multicomponent oleogel, foreseeing the hamburger production. The results show that the oleogel incorporation in meat patties is possible at the industrial level without additional unitary steps during meat patty production. Based on this work it is possible to produce meat patties with adjusted fatty acids profiles.  相似文献   
690.
The replacement of flexible polyolefin barrier layers with novel, thin, functional polymer coatings in the production of paperboard packaging involves the risk of deteriorated barrier and mechanical properties during the converting process. Local defects or cracks in the protective barrier layer can arise because of the stress induced in creasing and folding operations. In this study, the incorporation of microencapsulated self‐healing agents in coating formulations applied both by spot‐ and uniform‐coating techniques was studied. The preparation process of microcapsules with a hydrophobic core surrounded by a hydrophobically modified polysaccharide membrane in aqueous suspension was developed to obtain capsules fulfilling both the criteria of small capsule size and reasonably high solids content to match the requirements set on surface treatment of paperboard for enhancement of packaging functionality. The survival of the microcapsules during application and their effectiveness as self‐healing agents were investigated. The results showed a reduced tendency for deteriorated barrier properties and local termination of cracks formed upon creasing. The self‐healing mechanism involves the rupture of microcapsules local to the applied stress, with subsequent release of the core material. Crack propagation is hindered by plasticization of the underlying coating layer, while the increased hydrophobicity helps to maintain the barrier properties. Copyright © 2009 John Wiley & Sons, Ltd.  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