全文获取类型
收费全文 | 3833篇 |
免费 | 221篇 |
国内免费 | 238篇 |
专业分类
电工技术 | 107篇 |
综合类 | 401篇 |
化学工业 | 76篇 |
金属工艺 | 13篇 |
机械仪表 | 65篇 |
建筑科学 | 340篇 |
矿业工程 | 62篇 |
能源动力 | 50篇 |
轻工业 | 50篇 |
水利工程 | 48篇 |
石油天然气 | 1591篇 |
武器工业 | 4篇 |
无线电 | 264篇 |
一般工业技术 | 71篇 |
冶金工业 | 95篇 |
原子能技术 | 12篇 |
自动化技术 | 1043篇 |
出版年
2024年 | 3篇 |
2023年 | 14篇 |
2022年 | 40篇 |
2021年 | 54篇 |
2020年 | 68篇 |
2019年 | 36篇 |
2018年 | 45篇 |
2017年 | 100篇 |
2016年 | 121篇 |
2015年 | 130篇 |
2014年 | 242篇 |
2013年 | 178篇 |
2012年 | 246篇 |
2011年 | 278篇 |
2010年 | 199篇 |
2009年 | 241篇 |
2008年 | 235篇 |
2007年 | 274篇 |
2006年 | 292篇 |
2005年 | 263篇 |
2004年 | 227篇 |
2003年 | 198篇 |
2002年 | 145篇 |
2001年 | 82篇 |
2000年 | 107篇 |
1999年 | 96篇 |
1998年 | 79篇 |
1997年 | 66篇 |
1996年 | 45篇 |
1995年 | 52篇 |
1994年 | 61篇 |
1993年 | 28篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有4292条查询结果,搜索用时 109 毫秒
1.
国家电网公司信息化程度越来越高,单机运维审计系统产生的数据量日益增多,对海量数据高效率存储分析性能严重下降,系统稳定性降低。为满足国家电网当前对运维审计系统数据存储分析以及系统稳定性的需求,在Hadoop开源架构的基础上,本文提出基于Hadoop集群的海量数据分布式存储方法和基于Heartbeat的心跳检测技术,实现基于Hadoop的电力运维审计系统。〖JP2〗实验测试结果表明,基于Hadoop的电力运维审计系统相比单机系统可用性提高了8.42%,大大提升了存储分析海量数据的性能,具有系统工作稳定和服务不间断等优势。 相似文献
2.
3.
针对MooseFS元数据节点的单点故障问题,对MooseFS源码进行改造,为其增加一个热备的备元数据节点,并通过主备之间同步元数据,备节点回放操作日志等技术使得备元数据节点内存中的元数据时刻跟主元数据节点保持一致。当主元数据节点发生故障切换到备元数据节点后,备元数据节点无需从本地加载元数据即可快速接替主元数据节点对外提供服务。测试结果表明,备元数据节点本地和内存中的元数据均与主元数据节点保持一致,且故障恢复时间小于1 s。 相似文献
4.
With the rapid development in business transactions, especially in recent years, it has become necessary to develop different mechanisms to trace business user records in web server log in an efficient way. Online business transactions have increased, especially when the user or customer cannot obtain the required service. For example, with the spread of the epidemic Coronavirus (COVID-19) throughout the world, there is a dire need to rely more on online business processes. In order to improve the efficiency and performance of E-business structure, a web server log must be well utilized to have the ability to trace and record infinite user transactions. This paper proposes an event stream mechanism based on formula patterns to enhance business processes and record all user activities in a structured log file. Each user activity is recorded with a set of tracing parameters that can predict the behavior of the user in business operations. The experimental results are conducted by applying clustering-based classification algorithms on two different datasets; namely, Online Shoppers Purchasing Intention and Instacart Market Basket Analysis. The clustering process is used to group related objects into the same cluster, then the classification process measures the predicted classes of clustered objects. The experimental results record provable accuracy in predicting user preferences on both datasets. 相似文献
5.
Peter Adeoye Sopade 《International Journal of Food Science & Technology》2021,56(6):2651-2661
Digestograms of 101 published in vitro starch digestion were used to investigate slope discontinuities. Polynomial equations (1 to 3 orders) adequately described the first derivative of the digestograms. The derivative(s) of the equations revealed critical point(s). The third-order equation described (P ≤ 0.05) 17% of the digestograms as triphasic, the second- and third-order equations identified (P ≤ 0.05) 32% as biphasic, while 51% exhibited (P ≤ 0.05) monophasic digestograms. Using nonlinear regression with practical constraints, a modified first-order kinetic model (Dt = D0 + D∞−0 {1 − exp [−K t]}) described (r2 > 0.56, P ≤ 0.05) segments 1–3 of the digestograms. Rapid-slow and slow-rapid digestion rates were obtained, and maximum digestible starches, D∞, ≤100g/100g (dry) starch for an in-depth understanding of starch digestion. This is the first comprehensive objective approach for slope discontinuities in starch digestograms for consistency in modelling digestograms that advances starch digestion studies. 相似文献
6.
安全管理平台(SMP)是实现安全管理工作常态化运行的技术支撑平台,在实际应用中需要实时处理来自安全设备所产生的海量日志信息。为解决现有SMP中海量日志查询效率低下的问题,设计基于云计算的SMP日志存储分析系统。基于Hive的任务转化模式,利用Hadoop架构的分布式文件系统和MapReduce并行编程模型,实现海量SMP日志的有效存储与查询。实验结果表明,与基于关系数据的多表关联查询方法相比,该系统使得SMP日志的平均查询效率提高约90%,并能加快SMP集中管控的整体响应速度。 相似文献
7.
孙勇阁 《食品安全质量检测学报》2018,9(15):4148-4151
随着经济水平的提高,人们对食品安全的关注度提升,对食品企业的社会责任也有了更高要求,因此需要建立社会责任审计评价体系,用以规范食品企业的行为。审计评价体系的构建主要包括评价目标(总体目标和细分目标)、评价原则(客观性、全面性以及可持续性原则)、评价方法(对比分析法、定量与定性分析法)、评价内容(食品企业社会责任的7个方面)和评价标准(国家法律法规、ISO26000和食品安全国家标准)5方面。本文通过分析我国食品企业社会责任的践行现状,指出审计评价体系构建的重要作用。 相似文献
8.
A log statement is one of the key tactics for a developer to record and monitor important run-time behaviors of our system in a development phase and a maintenance phase. It composes of a message for stating log contents, and a log level (eg, debug or warn) to denote the severity of a message and controlling its visibility at run time. In spite of its usefulness, a developer does not tend to deeply consider which log level is appropriate in writing source code, which causes the system to be unmaintainable. To address this issue, this paper proposes an automatic approach to validating the appropriateness of the log level in consideration of the semantic and syntactic features and recommending a proper alternative log level. We first build the semantic feature vector to quantify the semantic similarity among application log messages using the word vector space, and the syntactic feature vector to capture the application context that surrounds the log statement. Based on the feature vectors and machine learning techniques, the log level is automatically validated, and an alternative log level is recommended if the log level is invalid. For the evaluation, we collected 22 open-source projects from three application domains, and obtained the 77% of precision and 75% of recall in validating the log levels. Also, our approach showed 6% higher accuracy than that of the developer group who has 7 to 8 years of work experience, and 72% of the developers accepted our recommendation. 相似文献
9.
Beate Eichmann Samuel Greiff Johannes Naumann Liene Brandhuber Frank Goldhammer 《Journal of Computer Assisted Learning》2020,36(6):933-956
In this explorative study, we investigate how sequences of behaviour are related to success or failure in complex problem-solving (CPS). To this end, we analysed log data from two different tasks of the problem-solving assessment of the Programme for International Student Assessment 2012 study (n = 30,098 students). We first coded every interaction of students as (initial or repeated) exploration, (initial or repeated) goal-directed behaviour, or resetting the task. We then split the data according to task successes and failures. We used full-path sequence analysis to identify groups of students with similar behavioural patterns in the respective tasks. Double-checking and minimalistic behaviour was associated with success in CPS, while guessing and exploring task-irrelevant content was associated with failure. Our findings held for both tasks investigated, from two different CPS measurement frameworks. We thus gained detailed insight into the behavioural processes that are related to success and failure in CPS. 相似文献
10.
浅析建设项目竣工决算审计与建设工程竣工结算审核的区别 总被引:1,自引:0,他引:1
从依据、工作程序及方法等诸多方面解析了建设项目竣工决算审计与建设工程竣工结算审核两者的区别,从而使今后的具体工作更具目的性、合理性. 相似文献