全文获取类型
收费全文 | 4380篇 |
免费 | 155篇 |
国内免费 | 64篇 |
专业分类
电工技术 | 38篇 |
综合类 | 497篇 |
化学工业 | 52篇 |
金属工艺 | 19篇 |
机械仪表 | 38篇 |
建筑科学 | 680篇 |
矿业工程 | 40篇 |
能源动力 | 101篇 |
轻工业 | 82篇 |
水利工程 | 23篇 |
石油天然气 | 13篇 |
武器工业 | 2篇 |
无线电 | 331篇 |
一般工业技术 | 275篇 |
冶金工业 | 471篇 |
原子能技术 | 1篇 |
自动化技术 | 1936篇 |
出版年
2023年 | 52篇 |
2022年 | 56篇 |
2021年 | 167篇 |
2020年 | 162篇 |
2019年 | 93篇 |
2018年 | 138篇 |
2017年 | 233篇 |
2016年 | 379篇 |
2015年 | 219篇 |
2014年 | 353篇 |
2013年 | 349篇 |
2012年 | 270篇 |
2011年 | 257篇 |
2010年 | 231篇 |
2009年 | 212篇 |
2008年 | 224篇 |
2007年 | 214篇 |
2006年 | 196篇 |
2005年 | 138篇 |
2004年 | 117篇 |
2003年 | 125篇 |
2002年 | 97篇 |
2001年 | 80篇 |
2000年 | 29篇 |
1999年 | 38篇 |
1998年 | 18篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 12篇 |
1991年 | 4篇 |
1989年 | 5篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1968年 | 3篇 |
1966年 | 4篇 |
1965年 | 3篇 |
1964年 | 6篇 |
1963年 | 3篇 |
1962年 | 4篇 |
1961年 | 10篇 |
1958年 | 3篇 |
1956年 | 2篇 |
1955年 | 3篇 |
1954年 | 3篇 |
排序方式: 共有4599条查询结果,搜索用时 15 毫秒
81.
The Rise of Twitter in the Political Campaign: Searching for Intermedia Agenda‐Setting Effects in the Presidential Primary
下载免费PDF全文
![点击此处可从《Journal of Computer-Mediated Communication》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bethany A. Conway Kate Kenski Di Wang 《Journal of Computer-Mediated Communication》2015,20(4):363-380
Questions exist over the extent to which social media content may bypass, follow, or attract the attention of traditional media. This study sheds light on such dynamics by examining intermedia agenda‐setting effects among the Twitter feeds of the 2012 presidential primary candidates, Twitter feeds of the Republican and Democratic parties, and articles published in the nation's top newspapers. Daily issue frequencies within media were analyzed using time series analysis. A symbiotic relationship was found between agendas in Twitter posts and traditional news, with varying levels of intensity and differential time lags by issue. While traditional media follow candidates on certain topics, on others they are able to predict the political agenda on Twitter. 相似文献
82.
Moritz Riesner Michael Netter Günther Pernul 《Information Security Technical Report》2013,17(4):185-198
The rising prevalence of Social Networking Sites (SNS) and their usage in multiple contexts poses new privacy challenges and increasingly prompts users to manage their online identity. To address privacy threats stemming from interacting with other users on SNS, effective Social Identity Management (SIdM) is a key requirement. It refers to the deliberate and targeted disclosure of personal attribute values to a subset of one's contacts or other users on the SNS. Protection against other entities such as the site operator itself or advertisers and application programmers is not covered by SIdM, but could be incorporated in further refinement steps. Features and settings to perform SIdM have been proposed and subsequently implemented partly by some SNS. Yet, these are often isolated solutions that lack integration into a reference framework that states the requirements for successfully managing one's identity. In this article, such a reference framework of existing and desired SIdM settings is derived from identity theory, literature analysis, and existing SNS. Based thereupon, we examine the SIdM capabilities of prevalent SNS and highlight possible improvements. Lastly, we reason about developing a metric to objectively compare the capability of SNS in regards to their support for SIdM. 相似文献
83.
Social media provide an online platform for enterprises to engage existing customers and attract new customers. Although social media can be easily set up at no cost, however, due to limited human and financial resources, many small businesses find it challenging to compete against large enterprises in social media use. While more and more small businesses have jumped on the bandwagon of social media in recent years, few studies investigated the social media strategies that can help small businesses to survive and even thrive against large competitors in the social media arena. Therefore, we studied 32 small pizzerias in a mid-size U.S. city in terms of their social media use for business. Our study found that small pizzerias emphasizing social media use on community relations and social responsibility tend to be more successful in attracting and engaging local customers. This study also sheds light on both effective strategies and successful practices of social media use by small pizzerias. The insights and recommendations identified from this study can help small businesses to enhance their social media competitiveness against large enterprises. 相似文献
84.
W. Ariyasriwatana W. Buente M. Oshiro D. Streveler 《New Review of Hypermedia and Multimedia》2013,19(4):317-340
Yelp, a social media site, undeniably has an influence on consumers' food choice in spite of its ability to reflect consumers' real voice being criticized. Since unhealthy food choices contribute to health problems, such as obesity and malnourishment, we attempted to examine these problems by better understanding consumers through health-related cues to action—a construct from the Health Belief Model (HBM)— on Yelp Honolulu's restaurant reviews. Our research revealed 13 main categories: Ingredient, Type of food, Taste, Lifestyle, Cooking, Option, Price, Portion, Well-being, Nutrition, Hygiene, Emotional attachment and indulgence, and Feeling. We argue that these categories may ultimately lead consumers to make healthier food choices. In search of the most appealing way to communicate with the target group, underlying concepts that derived from these categories can be tested. Marketers in food industry (or public health policy-makers) can craft their strategies for healthy food brands/products (or healthy eating scheme) based on the concept test research. Moreover, Yelp can apply these insights in the development of their algorithm and filter system in order to help consumers find healthy food if they wish to do so. Restaurants can also improve their strategy, menu, and communication execution to meet the growing demands of health conscious consumers. 相似文献
85.
86.
为提高《多媒体技术应用》实验教学的教学质量,提出"项目驱动,案例教学"法。通过课程设计实践,全面提升学生的计算机应用的技术技能和动手能力,将本学科知识和技术技能与自身专业有机地结合起来,为社会经济建设服务。实践证明,该教学方法对提高教学质量具有积极的促进作用。 相似文献
87.
随着网络不断地社会化、普及化,网络社区的规模也越来越大,这给社会化网络关系的计算带来了巨大的计算量。这些计算包括个人关系及计算与生成、全局关系计算与生成以及关系的挖掘等。虽然这些工作的计算量很大,但却适合并行处理。基于此,本文通过详细分析GPU的高性能运算及其在CUDA编程模型上的具体实现,讨论利用基于CUDA硬件架构的GPU来进行社区用户关系的并行计算。 相似文献
88.
靳霞 《电脑编程技巧与维护》2010,(18):55-57,62
社保基金档案管理系统是社会保险业务办理存档信息化的一个主要内容。系统是基于.NET技术采用完整的三层结构设计,使用VB.NET语言设计程序,提供了对业务数据档案的查询、修改及在系统和Excel数据文件间的批量导入与导出功能。对开发.NET管理信息系统有一定的借鉴意义。 相似文献
89.
本文介绍了今年6月14-15日在新加坡召开的iGOV2010全球论坛的主题和主旨报告,概述了社会协作网络对电子政府改革的深刻影响并对全球电子政府发展的若干动向作简要分析。 相似文献
90.
This study explores the relationship between the structure of an existing social network and the structure of an emergent discussion-board network in an undergraduate university class. Thirty-one students were issued with laptop computers that remained in their possession for the duration of the semester. While using these machines, participants' email log files were collected directly from the University's email servers. The analysis compared structural attributes of actors evident in their social network with the emergent structural properties measured from interactions in a shared discussion board environment. A significant relationship was found between the existing social network structure and the emergent communication patterns, suggesting that existing relationships have a strong influence on subsequent computer-mediated communication. Additional matrices were used to control for gender, major and perceived computer efficacy, none of which had a significant effect. 相似文献