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   1149篇
  免费   113篇
电工技术   4篇
综合类   3篇
化学工业   419篇
金属工艺   11篇
机械仪表   15篇
建筑科学   37篇
矿业工程   3篇
能源动力   17篇
轻工业   244篇
水利工程   9篇
石油天然气   8篇
无线电   41篇
一般工业技术   163篇
冶金工业   205篇
原子能技术   3篇
自动化技术   80篇
  2024年   5篇
  2023年   13篇
  2022年   26篇
  2021年   59篇
  2020年   41篇
  2019年   41篇
  2018年   48篇
  2017年   43篇
  2016年   51篇
  2015年   26篇
  2014年   62篇
  2013年   70篇
  2012年   95篇
  2011年   112篇
  2010年   57篇
  2009年   68篇
  2008年   69篇
  2007年   67篇
  2006年   68篇
  2005年   55篇
  2004年   49篇
  2003年   27篇
  2002年   27篇
  2001年   13篇
  2000年   11篇
  1999年   5篇
  1998年   8篇
  1997年   8篇
  1996年   4篇
  1995年   8篇
  1994年   5篇
  1993年   4篇
  1992年   1篇
  1990年   3篇
  1989年   3篇
  1988年   4篇
  1985年   1篇
  1978年   4篇
  1977年   1篇
排序方式: 共有1262条查询结果,搜索用时 15 毫秒
21.
The information and communication technology infrastructure available in rural and remote areas may often not have the bandwidth to support all types of telehealth applications; therefore, for example, some traditionally envisaged videoconferencing-based telehealth applications may not be able to be used or not used in their anticipated form at this time. While the level of broadband services available may impose limitations on these types of telehealth applications, in this review article, we identify applications that allow the maximizing of telehealth benefits in the presence of low-bandwidth connectivity and have potential benefits well-matched to rural and remote area healthcare challenges. In particular, we include consideration of how ubiquitous computing might potentially bring non-traditional approaches to telehealth that can also come into usage more immediately in bandwidth-constrained rural and regional areas. In this article, we review the benefits of ubiquitous computing for rural and remote telehealth including social media-based preventative, peer support and public health communication, mobile phone platforms for the detection and notification of emergencies, wearable and ambient biosensors, the utilization of personal health records including in conjunction with mobile and sensor platforms, chronic condition care and management information systems, and mobile device–enabled video consultation.  相似文献   
22.
23.
24.
Heart disease is the number one killer in the United States, and finding indicators of the disease at an early stage is critical for treatment and prevention. In this paper we evaluate visualization techniques that enable the diagnosis of coronary artery disease. A key physical quantity of medical interest is endothelial shear stress (ESS). Low ESS has been associated with sites of lesion formation and rapid progression of disease in the coronary arteries. Having effective visualizations of a patient's ESS data is vital for the quick and thorough non-invasive evaluation by a cardiologist. We present a task taxonomy for hemodynamics based on a formative user study with domain experts. Based on the results of this study we developed HemoVis, an interactive visualization application for heart disease diagnosis that uses a novel 2D tree diagram representation of coronary artery trees. We present the results of a formal quantitative user study with domain experts that evaluates the effect of 2D versus 3D artery representations and of color maps on identifying regions of low ESS. We show statistically significant results demonstrating that our 2D visualizations are more accurate and efficient than 3D representations, and that a perceptually appropriate color map leads to fewer diagnostic mistakes than a rainbow color map.  相似文献   
25.
The present research examined disclosure in online social networking profiles (i.e., FACEBOOK™). Three studies were conducted. First, a scoring tool was developed in order to comprehensively assess the content of the personal profiles. Second, grouping categories (default/standard information, sensitive personal information, and potentially stigmatizing information) were developed to examine information pertinent to identity threat, personal and group threat. Third, a grouping strategy was developed to include all information present in FACEBOOK™, but to organize it in a meaningful way as a function of the content that was presented. Overall, approximately 25% of all possible information that could potentially be disclosed by users was disclosed. Presenting personal information such as gender and age was related to disclosure of other sensitive and highly personal information. Age and relationship status were important factors in determining disclosure. As age increased, the amount of personal information in profiles decreased. Those seeking a relationship were at greatest risk of threat, and disclosed the greatest amount of highly sensitive and potentially stigmatizing information. These implications of these findings with respect to social and legal threats, and potential means for identifying users placing themselves at greatest risk, are discussed.  相似文献   
26.
Jansen  Bernard J.  Goodrum  Abby  Spink  Amanda 《World Wide Web》2000,3(4):249-254
The development of digital libraries has enhanced the integration of textual and multimedia information in many document collections. The World Wide Web provides the connectivity for many digital library users. Studies exploring the searching characteristics of Web users are an important and a growing area of research. Most Web user studies have focused on general Web searching, regardless of subject matter or format. Little research has examined how Web users search for multimedia information. Our study examines users' multimedia searching on a major Web search service. The data set examined consisted of 1,025,908 queries from 211,058 users of Excite ®, a major Web search service. From this data set, we identified and analyzed queries for audio, image, and video queries. Our findings were compared to results from general Web searching studies. Implications for the design of Web searching services and interfaces are discussed.  相似文献   
27.
Nearshore small fish species represent a large proportion of fish biodiversity in Lake Simcoe, a large inland lake in southern Ontario, Canada. Over the past 30 years, Lake Simcoe has experienced several changes to its aquatic habitat, benthic invertebrate communities and predatory fish populations. This study compared samples of the nearshore small fish community in three geographic areas of Lake Simcoe. Fish community data were grouped into two time periods: a contemporary period (2007–2009) and a historical period (1982–1995). The fish community was compared across time periods for each area to assess if observed ecological changes had an impact on the small fish community. Species richness significantly declined between time periods in two areas (Cook's Bay and the southeast shoreline), the number of individuals captured declined between time periods in one area of the lake (Kempenfelt Bay) and Simpson's diversity index declined between time periods in one area of the lake (southeast shoreline). There were no significant differences in the Shannon–Weiner evenness index between time periods in any of the study areas. Additional analyses of intra- and inter-annual variation in fish sampling results generally supported the findings that shifts in the fish community occurred between time periods. Overall, this study suggests that the nearshore small fish biodiversity of Lake Simcoe has shifted over time but these shifts are not clearly related to recent increases in water clarity, macrophyte growth and nearshore benthic invertebrate densities.  相似文献   
28.
This study explored the moderating effects of children's neighborhoods on the link between hostile parenting and externalizing behavior. Participants were 1st- or 2nd-grade children in an urban northeastern community. Children were administered the Parenting and Neighborhood scales of the Child Puppet Interview, and mothers completed questionnaires on neighborhood quality and parenting practices. Census tract measures of neighborhood quality and teachers' reports of children's externalizing behavior also were obtained. Results indicated that children's and mothers' perceptions of neighborhood involvement-cohesion buffered the link between hostile parenting and externalizing problems. Children's externalizing behavior was unrelated to census tract variables. Findings highlight the protective effect of neighborhood social cohesion and the utility of including young children's perspectives in research on neighborhoods and families. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
29.
Relations of overt and relational aggression with perceived popularity among children and early adolescents were examined in 2 studies (Ns = 607 and 1,049). Among older youths, positive concurrent relations found between overt aggression and perceived popularity became nonsignificant when relational aggression was controlled, whereas positive associations found between relational aggression and perceived popularity held when overt aggression was controlled. Aggression and perceived popularity were not positively related for the younger participants. The 2nd study also examined the temporal ordering of these relations over 6 months. For older girls, positive relations between relational aggression and perceived popularity were bidirectional. For older boys, relational aggression did not predict increased perceived popularity, but perceived popularity predicted increased relational aggression. Implications for intervention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
30.
The authors examined the contributions of infant's temperament and parent's personality to their relationship. In Study 1, 102 infants, mothers, and fathers were studied when infants were 7 months; in Study 2, 112 infants and mothers were followed from 9 to 45 months. Infants' temperament (joy, fear, anger, and attention) was observed in standard temperament paradigms. Parents' personality measures encompassed the Big Five traits and Empathy in Study 1 and Mistrust, Manipulativeness, Aggression, Dependency, Entitlement, and Workaholism in Study 2. Parent-child relationship (shared positive affect and parental responsiveness in Studies 1 and 2 and parental tracking of the infant in Study 1) was observed in naturalistic contexts. In Study 1, mothers' Neuroticism, Empathy, and Conscientiousness and fathers' Agreeableness, Openness, and Extraversion related to the relationship with the infants. All measures of infant temperament also related to the emerging relationship. In Study 2, maternal Mistrust, Manipulativeness, Dependency, and Workaholism predicted the relationship with the child. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  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