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   191篇
  免费   6篇
综合类   1篇
化学工业   13篇
建筑科学   9篇
矿业工程   8篇
能源动力   2篇
轻工业   81篇
水利工程   16篇
无线电   30篇
一般工业技术   15篇
自动化技术   22篇
  2021年   1篇
  2018年   2篇
  2017年   1篇
  2016年   2篇
  2015年   13篇
  2014年   9篇
  2013年   8篇
  2012年   10篇
  2011年   7篇
  2010年   6篇
  2009年   5篇
  2008年   8篇
  2007年   35篇
  2006年   25篇
  2005年   25篇
  2004年   3篇
  2003年   13篇
  2002年   2篇
  2001年   4篇
  1993年   1篇
  1992年   1篇
  1983年   3篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1973年   1篇
  1922年   1篇
  1918年   1篇
  1914年   1篇
  1908年   2篇
排序方式: 共有197条查询结果,搜索用时 15 毫秒
11.
2008年9月12日,由中国木材流通协会、美国大自然保护协会、森林趋势主办的,中国家具协会、美国林业及纸业协会、上海木材行业协会协办的“美国欧盟木制品合法贸易立法进展情况通报会”在上海召开。会上主要就美国新出台的关于林产品合法贸易的法案——《雷斯法案》(Lacey Act)修正案作了介绍,美国司法部环境与资源司的副司长古兹曼律师(Michael J.Guzman)回答了与会者的提问;  相似文献   
12.
The dual of an optimization problem with piecewise linear, convex, and continous objective function and linear restrictions is investigated. It is shown that the dual problem is of the same type as the primal and can be solved by the same methods as were proposed in a previous work of the author. Experiences arising from the application of different variants of these methods to solve a number of examples, where the primal as well as the dual version was employed, are reported.  相似文献   
13.
This Mag. 《家具》2005,(5):15-17
台资家具企业进入中国大陆已有十多年的历史了,并且发展迅速。2004年,从中国大陆出口的约103亿美元的家具总出口额中,台资企业占了56亿美元。台资企业在中国家具业中占有了这么重要的位置,但由于信息渠道的原因,我们对台资企业在中国大陆的发展状况一直了解不多。这次,本刊有幸采访到台湾家具工业同业公会的理事长陈丘先生,请他全面介绍了台资家具企业在中国大陆的发展状况。  相似文献   
14.
This Mag 《家具》2005,(5):53-53
2005年9月14日晚,近200名来自国家及地方行业组织、国家技术监督管理部门、业内知名企业以及媒体的代表在上海浦东举行上海市木工机械同业联谊会成立大会。该会旨在搭建上海木工机械企业交流的平台.推动同业企业合作,引导同业企业规范竞争行为,促进同业企业健康发展。  相似文献   
15.
This Mag 《家具》2005,(5):i0004-i0005
总体概况 第十四届国际名家具(东莞)展览会于2005年8月17日至21日在东莞厚街成功举办,5天展期共接待专业观众87160人,其中海外专业买家8510人,与去年同比增长近40%,海外买家在名家具展的停留时间,人均已经达到32天.  相似文献   
16.
The behavioral activity of some trifluoromethyl ketones (TFMKs) as inhibitors of the pheromone activity of the corn stalk borer Sesamia nonagrioides (Lef.) (Lepidoptera: Noctuidae) is reported. The most closely-related analogue to the pheromone tested, (Z)-11-hexadecenyl trifluoromethyl ketone (Z11-16:TFMK), elicited a significant decrease in the number of male catches in traps baited with mixtures with the pheromone in 1:1 and 10:1 ratios in comparison to the pheromone alone. The E isomer of the analogue as well as two highly hydrated ketones, 3-octylthio-1,1,1-trifluoropropan-2-one (OTFP) and 1,1-difluoropentadecyl trifluoromethyl ketone, were inactive. Conversely, the saturated TFMKs n-dodecyl trifluoromethyl ketone and, particularly, n-hexadecyl trifluoromethyl ketone induced a synergistic effect when mixed with the synthetic pheromone in 10:1 ratio. However, in a wind tunnel these chemicals did not elicit any differential effect on flying moths attracted to a source containing a 10:1 blend of the analogue and the pheromone. In a dual choice bioassay with two dispensers, containing the pheromone alone, and mixtures of Z11-16:TFMK and the pheromone and separated 5 cm apart, males showed no particular preference for either dispenser. The ketone mixture, however, induced moths to execute erratic flights with frequent crosswind counter-turns and intersections with plume boundaries. The total number of contacts with the source were reduced when a control dispenser was paired with a dispenser containing Z11-16:TFMK and pheromone. Z11-16:TFMK and OTFP showed little toxicity on mice with a LD50 of 1 g/kg after the 6th day of treatment. For comparitive purposes, the major component of the pheromone, Z11-16:Ac, displayed a LD50 of 5 g/kg 6 days after application. Our results provide additional information about the activity of the TFMKs, which might be useful for the utilization of these chemicals in future pest control studies.  相似文献   
17.
The EU Water Framework Directive commits member states to achieve good ecological status in all waterbodies. Artificial or heavily modified waterbodies must reach at least its good ecological potential. In view of these requirements, simple and feasible methods are required in order to evaluate habitat suitability for relevant target species in larger river reaches. Well-developed models for determining the relationship between stream flows and habitat for target species mainly based on micro- and meso-scale already exist. However, the application of such models is complex and time-consuming and consequently limited to relatively short river segments. The objective of this study is to develop a simplified applicable assessment model to evaluate habitat conditions for selected target fish. This model uses hydro-morphological indicators for the habitat assessment and relies on correlative relations between habitat suitability and hydro-morphological features of river stretches (average Froude-number, relative flow width, mean bed slope, relative water depth and flow velocity). The indicators were determined as reach-related averages, derived from 2D model simulations (hydraulic and habitat-specific). Particular emphasis was laid on using a wide range of river stretches with different hydro-morphological characteristics (hydrology, bed substratum, bed structures, degree of braiding, sinuosity of the river course, mean bed width and bed slope). As a result, a set of model equations enables the evaluation of fish habitat conditions in river stretches as a function of flow and morphology. The habitat suitability assessment focuses on four preselected target species: brown trout, European grayling and for low slope rivers common nase and barbel.  相似文献   
18.
The multiple uses of the Danube River for navigation, hydropower production and as a drinking water supply influence its ecological quality. Flow restrictions due to regulation as well as impacts on the sediment regime such as retention in the catchment area and interruption of the sediment continuum result in changes of the hydromorphological structures and can produce major problems in the context of sediment management. In light of these facts, cross-border investigations of sediment transport at the Danube River are called for. As there are no uniform research approaches shared by Austria and Hungary, the EU-funded project SEDDON (Sediment Research and Management at the Danube River) aims to compare different monitoring and modeling techniques used to determine sediment transport, and to develop mutual solutions. Further, the laboratory equipment currently used for hydraulic model experiments is evaluated and a research channel with a free flowing discharge of up to 10 m3/s without pumping will be constructed, allowing large-scale joint laboratory tests concerning sediment to be performed.  相似文献   
19.
Due to the increasing importance of producing and consuming energy more sustainably, Energy Informatics (EI) has evolved into a thriving research area within the CS/IS community. The article attempts to characterize this young and highly dynamic field of research by describing current EI research topics and methods and provides an outlook of how the field might evolve in the future. It is shown that two general research questions have received the most attention so far and are likely to dominate the EI research agenda in the coming years: How to leverage information and communication technology (ICT) to (1) improve energy efficiency, and (2) to integrate decentralized renewable energy sources into the power grid. Selected EI streams are reviewed, highlighting how the respective research questions are broken down into specific research projects and how EI researchers have made contributions based on their individual academic background.  相似文献   
20.
Investment advisory services of financial service providers (FSPs) exhibit several characteristics that are detrimental to advisory quality. The interaction of advisor and client is strained by a lack of transparency regarding the advisory process (what activities are performed and why) and the information used therein (what information is used for what purpose and with what effect), as well as regarding the precise costs of the service and the recommended products. In prior research, we suggested that process and information transparency issues may be appropriately addressed with collaborative information technology (IT) artifacts. In this paper, we argue that collaborative, transparent artifacts may also be a premise of enabling cost transparency. To this end, we describe a complete research cycle of designing, implementing, and evaluating a shared cost-transparent IT artifact to support client-advisor interaction in investment advisory encounters. Evaluation results suggest the efficacy of our design in improving the clients?? perceived cost transparency as well as increase their satisfaction and their willingness to pay for the received investment advice. These findings may also challenge the common belief of FSPs that transparent, fee-based advisory services would neither be accepted by clients nor be economically viable. Practical implications of these findings for designing advisory encounters with supportive IT are discussed.  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