全文获取类型
收费全文 | 4679篇 |
免费 | 528篇 |
国内免费 | 123篇 |
专业分类
电工技术 | 165篇 |
综合类 | 600篇 |
化学工业 | 141篇 |
金属工艺 | 39篇 |
机械仪表 | 83篇 |
建筑科学 | 1394篇 |
矿业工程 | 697篇 |
能源动力 | 96篇 |
轻工业 | 307篇 |
水利工程 | 314篇 |
石油天然气 | 297篇 |
武器工业 | 26篇 |
无线电 | 166篇 |
一般工业技术 | 195篇 |
冶金工业 | 275篇 |
原子能技术 | 56篇 |
自动化技术 | 479篇 |
出版年
2024年 | 6篇 |
2023年 | 58篇 |
2022年 | 111篇 |
2021年 | 170篇 |
2020年 | 177篇 |
2019年 | 88篇 |
2018年 | 98篇 |
2017年 | 111篇 |
2016年 | 149篇 |
2015年 | 172篇 |
2014年 | 375篇 |
2013年 | 327篇 |
2012年 | 307篇 |
2011年 | 365篇 |
2010年 | 280篇 |
2009年 | 288篇 |
2008年 | 281篇 |
2007年 | 290篇 |
2006年 | 247篇 |
2005年 | 239篇 |
2004年 | 205篇 |
2003年 | 166篇 |
2002年 | 144篇 |
2001年 | 104篇 |
2000年 | 95篇 |
1999年 | 81篇 |
1998年 | 71篇 |
1997年 | 39篇 |
1996年 | 59篇 |
1995年 | 42篇 |
1994年 | 35篇 |
1993年 | 21篇 |
1992年 | 25篇 |
1991年 | 12篇 |
1990年 | 6篇 |
1989年 | 13篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 11篇 |
1985年 | 7篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1958年 | 2篇 |
1957年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有5330条查询结果,搜索用时 15 毫秒
1.
Containers, enabling lightweight environment and performance isolation, fast and flexible deployment, and fine-grained resource sharing, have gained popularity in better application management and deployment in addition to hardware virtualization. They are being widely used by organizations to deploy their increasingly diverse workloads derived from modern-day applications such as web services, big data, and internet of things in either proprietary clusters or private and public cloud data centers. This has led to the emergence of container orchestration platforms, which are designed to manage the deployment of containerized applications in large-scale clusters. These systems are capable of running hundreds of thousands of jobs across thousands of machines. To do so efficiently, they must address several important challenges including scalability, fault tolerance and availability, efficient resource utilization, and request throughput maximization among others. This paper studies these management systems and proposes a taxonomy that identifies different mechanisms that can be used to meet the aforementioned challenges. The proposed classification is then applied to various state-of-the-art systems leading to the identification of open research challenges and gaps in the literature intended as future directions for researchers. 相似文献
2.
煤矿开采是在地层中进行的,不可避免地受到地质条件的影响。很多煤矿灾害的发生与地质构造有关,因此了解煤矿开采中的地质构造十分有必要。为了了解煤层的地质构造,必须对煤矿地质条件进行测量。分析了煤矿地质测量对安全生产的作用,并提出了一些措施来提升煤矿地质测量的有效性,可以为煤矿地质测量工作人员提供一定的参考。 相似文献
3.
针对5G基站设备相对于以往2G/3G/4G设备的变化,面向一线勘察设计人员,阐述5G基站在供配电需求方面功耗增大、供电方式多样化、供配电改造工作量和难度加大等相应变化,归纳相应的勘察前期准备工作要点,分析在实际工作中可能面临的外市电引入改造、供电方式选择的多样性、新型锂电池应用等重点、难点,介绍理想的5G供配电模式及发展方向,最后提出5G基站供配电勘察设计工作思路调整的建议。 相似文献
4.
Yajun Zhang Shan Liu Jing Tan Guoyin Jiang Qing Zhu 《International Journal of Project Management》2018,36(4):627-639
Although business process outsourcing (BPO) can reduce cost and enhance the competitiveness of firms, the implementation of BPO projects is unsatisfactory. By integrating knowledge management capability theory and risk-based view, we develop a model of how different types of BPO risks affect project satisfaction and how knowledge management capability changes the influences of BPO risks. A survey of 121 BPO projects was conducted among BPO client department manager and project manager through a pairwise design. Empirical evidence reveals that social system, technical system, and project management risks negatively affect BPO project satisfaction. However, cultural, technological, and structural levels of knowledge management capabilities weaken the negative risk effects of social system, technical system, and project management, respectively. Different types of risks and knowledge management capabilities should be matched to achieve effective risk management. 相似文献
5.
《The Electricity Journal》2020,33(7):106802
The paper aims to investigate the determinants of household electricity consumption in Korea by using both the OLS regression and quantile regression. The results show that the effects of socio-demographic, dwelling, and electricity consumption characteristics on household electricity consumption may differ between two regressions and may differ across quantiles. We found that age group of household head, number of household, housing area, the number of household appliances, and refrigerator usage time were significant in all quantiles. 相似文献
6.
在煤矿测量工作中,贯通测量是其中重要工作之一,确保贯通点的误差在设定的范围内,决定了贯通测量的成败。本文将马脊梁煤矿副立井与王村回风立井的贯通作为研究对象,选择使用井下控制测量、竖井联系测量及陀螺定向技术等,设定了贯通测量的方案,开展了误差预计,通过对比预计结果和要求,保证了贯通测量设计的可行性。 相似文献
7.
目的:了解北京市中学生营养知识掌握现况并探讨影响因素。方法:采用整群典型抽样,抽取北京核心城区和郊县城区数所代表性中学学生,开展现场问卷调查。结果:北京市6所中学1192名学生参与问卷调查,其中初中生789人、高中生392人,男生600人(50.80%)、女生581人(49.20%),平均年龄13.72±1.58岁(最小11岁、最大19岁);中学生营养知识平均得分为59.37,初中生59.78,高中生58.53;女生61.08,男生57.71;学生对不同类别营养知识的知晓率差异显著(P<0.05);女性学生、与父母同住、父母学历高与学生营养知识得分存在正相关关系。结论:北京市中学生营养知识得分处于不及格水平,对不同知识类别的知晓度差异显著,学生在初高中阶段学习和掌握营养知识缺乏系统连贯性。学校课程设置、年级、性别、父母学历、居住状况等影响学生营养知识掌握状况。学校应考虑家庭和社会参与,衔接初高中阶段课程教学,加强系统、综合和连贯性的学生营养教育。 相似文献
8.
GPS测量技术在测绘领域中的应用价值相当突出,有着不可替代的作用和地位。同时,基于CORS系统下GPS测量技术因为具备精准定位、高效率定位等特点,在行业当中被许多人士认可。对此,为了更好的提高GPS测量技术的应用价值,详细分析基于CORS系统下GPS测量技术,希望可以今后相关工作者提供理论性帮助。 相似文献
9.
Feeling thermometer questions are widely used in political science research to estimate people’s attitudes and feelings toward a political object, like a political figure or an organization. Given the popularity of the feeling thermometer question in population surveys, more work is needed to explore the measurement of this question type. This study examines the data collection mode effect on feeling thermometers. Using the 2012 American National Election Studies, we find that the measurement of feeling thermometers is not exactly comparable between face-to-face and Web surveys. Face-to-face respondents tend to provide warmer feelings, while Web respondents give relatively more reliable responses in comparison. In both survey modes, respondents are most likely to select the response options that are verbally labeled although the effect is more striking in face-to-face than Web survey. The item nonresponse between these two modes does not differ in a meaningful way. This study ends by discussing future research directions on feeling thermometer questions. 相似文献
10.