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   1093篇
  免费   39篇
电工技术   13篇
综合类   1篇
化学工业   123篇
金属工艺   15篇
机械仪表   39篇
建筑科学   31篇
矿业工程   1篇
能源动力   26篇
轻工业   121篇
水利工程   16篇
石油天然气   2篇
武器工业   1篇
无线电   83篇
一般工业技术   158篇
冶金工业   325篇
原子能技术   10篇
自动化技术   167篇
  2023年   6篇
  2022年   12篇
  2021年   16篇
  2020年   4篇
  2019年   19篇
  2018年   29篇
  2017年   22篇
  2016年   25篇
  2015年   21篇
  2014年   31篇
  2013年   46篇
  2012年   45篇
  2011年   61篇
  2010年   44篇
  2009年   50篇
  2008年   40篇
  2007年   57篇
  2006年   39篇
  2005年   42篇
  2004年   39篇
  2003年   38篇
  2002年   32篇
  2001年   26篇
  2000年   25篇
  1999年   28篇
  1998年   54篇
  1997年   43篇
  1996年   26篇
  1995年   28篇
  1994年   16篇
  1993年   15篇
  1992年   11篇
  1990年   5篇
  1989年   10篇
  1988年   6篇
  1987年   4篇
  1985年   6篇
  1984年   4篇
  1983年   7篇
  1979年   5篇
  1978年   11篇
  1977年   9篇
  1976年   5篇
  1974年   3篇
  1954年   5篇
  1944年   7篇
  1943年   10篇
  1940年   3篇
  1939年   5篇
  1937年   4篇
排序方式: 共有1132条查询结果,搜索用时 9 毫秒
1.
2.
This study focuses on the relationship between photo-catalytic performance and optical property over Si-incorporated TiO2. The Si-incorporated TiO2 particles exhibited a pure structure of anatase having a particle size of less than 20 nm and surface area of more than 190 m2/g. The absorbance did not shift to a higher wavelength in spite of the incorporation of the Si ions, but the intensity of the photoluminescence (PL) curve was the smallest in the case of the 2.0 mol% Si-TiO2, which was related to the recombination between the excited electrons and holes. Based on these results, the photodecomposition of methyl orange in the liquid reaction was enhanced over the 2.0 mol% Si-incorporated TiO2 compared with that over pure TiO2: Methyl orange at 10.0 ppm was completely decomposed after 100 min when 1.0 g of the 2.0 mol% Si-incorporated TiO2 was used.  相似文献   
3.
This paper reviews the current state of industry with regard to the introduction of software metrics. It discusses the benefits that organizations have derived from metrication, it looks at why organizations have sought to introduce metrics programmes, how they have gone about introducing those programmes and the problems that they have encountered during implementation. The review found that, on the whole, only the sanitized aspects of metrics experiences have actually been published. This seems to be especially the case with respect to practitioner resistance. Very few organizations admit to having encountered resistance during the introduction of a metrics programme. The paper also includes the results of a pilot study, conducted by the first author, which examines the attitudes that developers hold towards the introduction of software metrics. The key findings of this pilot study are that positive attitudes to metrics correlate highly with levels of education and to job satisfaction.  相似文献   
4.
Premature and ill term babies born in regional Australia must be moved to another hospital with Neonatal Intensive Care Unit (NICU) facilities. Transferred pre-term and critically ill term babies have higher mortality rates and much higher rates of long term disability than similar babies born in hospitals with NICU facilities. This paper details the Bush Babies Broadband project that aims to significantly improve the quality of treatment for babies born in rural, remote as well as urban areas by providing the first on-demand virtual NICU architecture in Australia. Real-time data collected from medical monitors and ventilators attached to the baby, audiovisual streams and static physiological data such as X-ray images are transmitted to the consulting Neonatologist to gain a better picture of the patient's condition than is currently available. The key contribution of this significant research is the infrastructure providing a mechanism for Neonatologists to receive information directly from a regional hospital, thereby preventing, in some cases, the immediate need to move the baby. A key benefit of this framework is that it is available to link regional hospitals with the supporting NICU Neonatologist ‘on demand’ eliminating the need to establish permanent point to point connections. This paper further describes the application of that architecture to a specific pilot connecting the Bathurst regional hospital with Neonatologists within the NICU at Nepean Hospital, Penrith Australia.  相似文献   
5.
Data from 10 sampling sites along the River Njoro are used to examine the contribution of nutrients from upstream land uses draining each of the sampling sites. The data also are used to assess whether both the proportion of land uses and the size of the subwatersheds account for the variability in water quality in the River Njoro watershed. Geographical Information System analysis was used to determine the spatial distribution of land‐cover types and subwatersheds contributing run‐off to the sampling sites in the River Njoro. Standard Digital Elevation Model‐based routines were used to establish the watershed area contributing run‐off to each sampling site. Water and sediment samples were collected for chemical analysis, and the nutrient levels were related to the upstream land‐use types and the size of the subwatersheds. The mid‐stream portion of the River Njoro (near Egerton University) accounts for the highest nutrient contributions. The percentage contribution is magnified by additions from industrial, human settlements and agricultural land uses around the University. There is a significant decrease in nutrient levels downstream, however, indicating natural purification as the river flows through an area of large‐scale farming with intense, well‐preserved riparian and in‐stream vegetation. Steep slopes of the land upstream of Egerton University enhance erosion and nutrient losses from those subwatersheds. Mixed small‐scale agricultural and bare lands contribute over 55% of the phosphorus load to the upper and mid‐reaches of the River Njoro. The size of the subwatershed accounts for about 53% of the variability in the soluble phosphorus in the river. The land‐use subwatershed proportions are important for characterizing and modelling water quality in the River Njoro watershed. Upland land uses are as important as near‐stream land uses. We suggest that conservation of intact riparian corridor along the river and its tributaries contributes significantly to natural purification processes and recovery of the ecological integrity of the River Njoro ecosystem.  相似文献   
6.
This study relates to the development of coatings for optical discs in high-density digital versatile disc systems (HD-DVD or blue lay disk) that use a high numerical aperture of 0.85 at 405 nm wavelength and have a protective top layer over a primer layer for protection against damage and dust. Ultraviolet-curable raw materials of two acrylic monofunctional monomers ( isobornylacrylate, IBA and tetrahydrofurfurylacrylate, THFA) and two kinds of urethaneacrylate oligomers (OUMD and OUME) have been easily mixed with photoinitiators. Curing rate of these materials was characterized by FT-IR. In case of top coats, VTES (vinyltriethoxysilane) and acrylic acid were added to enhance the abrasion resistance. These two kinds of UV-curable resinous materials having no solvent were synthesized and investigated as means for making a blue ray disk having good optical and mechanical properties. In addition, dynamic characteristics including reflectivity, fluctuation of RF signal and noise level were also investigated.  相似文献   
7.
Conducted a prospective examination of the effects of naturally occurring partner support on smoking cessation maintenance with 125 newly abstinent female smokers (mean age 41.8 yrs). 123 of the Ss were married, and 2 were living with a partner. Six days after smoking cessation, Ss supplied demographic and smoking habit data and ratings of a variety of their own and their partners' attributes and behaviors. Factor analysis of partner ratings revealed a dominant factor, Partner Facilitation, which accounted for 74% of the common variance, encompassed both quitting-related and general interactions, and loaded on the following behaviors: problem solving, rewarding quitting, understanding, listening, and facilitating the enactment of coping and nonsmoking skills. Results indicate that when the Partner Facilitation factor was entered into a stepwise discriminant analysis with 19 other variables, it emerged as the primary predictor of smoking cessation maintenance, accounting for 32% of the variance in outcome at 6–8 wks and accurately identifying more than 80% of both successful and unsuccessful outcomes. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
8.
9.
10.
Companies across industries have admired the success of Dell Computersin using modularity as part of a mass customization strategy to achieve build-to-order and a streamlined supply chain. Many companies are attempting to emulate this successful model, including the American automotive industry. This paper focuses on how the auto industry has been attempting to move to modularity, in part, motivated by a desire to build cars to order. This movement has led to major changes in supply chain practices based partly on imitation of successful keiretsu models in Japan and a move toward modules. This study finds significant impact of modularity on outsourcing, product development, and supply chain coordination based on interviews conducted with automakers and suppliers from 2000-2003. Based on our interviews, we observe that modularity has accompanied a major reorganization of the automotive supplier industry. We identify two major issues that appear to block U.S. automakers from gaining most of the advantages possible through modularity. First, most modularity activities appear to be primarily strategically cost reduction driven, leaving the potential of modularity for mass customization largely untapped. Second, the shift in industry reorganization has not been accompanied by changes in the supply chain infrastructure to encourage long-term partnerships. We contrast this to the more gradual approach used by Toyota as it incorporates modularity on a selective basis and moves to a build-to-order model  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