全文获取类型
收费全文 | 305篇 |
免费 | 24篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 22篇 |
综合类 | 26篇 |
化学工业 | 18篇 |
金属工艺 | 10篇 |
机械仪表 | 37篇 |
建筑科学 | 27篇 |
矿业工程 | 6篇 |
能源动力 | 13篇 |
轻工业 | 2篇 |
水利工程 | 5篇 |
石油天然气 | 5篇 |
武器工业 | 5篇 |
无线电 | 44篇 |
一般工业技术 | 25篇 |
冶金工业 | 5篇 |
原子能技术 | 4篇 |
自动化技术 | 88篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 15篇 |
2013年 | 18篇 |
2012年 | 13篇 |
2011年 | 16篇 |
2010年 | 18篇 |
2009年 | 21篇 |
2008年 | 14篇 |
2007年 | 24篇 |
2006年 | 20篇 |
2005年 | 17篇 |
2004年 | 11篇 |
2003年 | 13篇 |
2002年 | 14篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 14篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有342条查询结果,搜索用时 47 毫秒
1.
The deterministic and probabilistic prediction of ship motion is important for safe navigation and stable real-time operational control of ships at sea. However, the volatility and randomness of ship motion, the non-adaptive nature of single predictors and the poor coverage of quantile regression pose serious challenges to uncertainty prediction, making research in this field limited. In this paper, a multi-predictor integration model based on hybrid data preprocessing, reinforcement learning and improved quantile regression neural network (QRNN) is proposed to explore the deterministic and probabilistic prediction of ship pitch motion. To validate the performance of the proposed multi-predictor integrated prediction model, an experimental study is conducted with three sets of actual ship longitudinal motions during sea trials in the South China Sea. The experimental results indicate that the root mean square errors (RMSEs) of the proposed model of deterministic prediction are 0.0254°, 0.0359°, and 0.0188°, respectively. Taking series #2 as an example, the prediction interval coverage probabilities (PICPs) of the proposed model of probability predictions at 90%, 95%, and 99% confidence levels (CLs) are 0.9400, 0.9800, and 1.0000, respectively. This study signifies that the proposed model can provide trusted deterministic predictions and can effectively quantify the uncertainty of ship pitch motion, which has the potential to provide practical support for ship early warning systems. 相似文献
2.
Weiwei Yu Pavla Vaneckova Xiaochuan Pan 《The Science of the total environment》2010,408(17):3513-3437
Background
A number of studies have examined the relationship between high ambient temperature and mortality. Recently, concern has arisen about whether this relationship is modified by socio-demographic factors. However, data for this type of study is relatively scarce in subtropical/tropical regions where people are well accustomed to warm temperatures.Objective
To investigate whether the relationship between daily mean temperature and daily all-cause mortality is modified by age, gender and socio-economic status (SES) in Brisbane, Australia.Methods
We obtained daily mean temperature and all-cause mortality data for Brisbane, Australia during 1996-2004. A generalised additive model was fitted to assess the percentage increase in all deaths with every one degree increment above the threshold temperature. Different age, gender and SES groups were included in the model as categorical variables and their modification effects were estimated separately.Results
A total of 53,316 non-external deaths were included during the study period. There was a clear increasing trend in the harmful effect of high temperature on mortality with age. The effect estimate among women was more than 20 times that among men. We did not find an SES effect on the percent increase associated with temperature.Conclusions
The effects of high temperature on all deaths were modified by age and gender but not by SES in Brisbane, Australia. 相似文献3.
文章重点从政策层面比较系统地回顾了中国建设行业注册建筑师执业管理制度从建立到发展演变的过程以及注册资格国际互认方面的情况。 相似文献
4.
This paper deals with the application of Chebychevʼs approximation theory to IIR digital filter frequency response (FR) approximation. It explores the properties of the frequency response of IIR digital filters as a nonlinear complex approximating function; IIR digital filter frequency response is used to approximate a prescribed magnitude and phase responses. The approximation problem is closely related to optimization. If the set of approximating functions is non-convex, the optimization problem is difficult and may converge to a local minimum. The main results presented in the paper are proposing a convex stability domain by introducing a condition termed “sign condition” and characterization of the best approximation by the Global Kolmogorovʼs Criterion (GKC). The Global Kolmogorovʼs Criteria is shown to be also a necessary condition for the approximation problem. Finally, it is proved that the best approximation is a global minimum. The sign condition can be incorporated as a constraint in an optimization algorithm. 相似文献
5.
深井开采冲击地压与防治 总被引:1,自引:0,他引:1
用矿岩能量指标和岩爆倾向度等多因素评价作为岩爆发生条件的判据,对红透山铜矿的岩爆现象作了这性研究与监测,并介绍了防止岩爆发生的几项措施。 相似文献
6.
7.
规划、规范和规则是建设项目审批依据的三个基本来源,三者共同构成开发控制管理制度的三大核心体系。研究结合深圳实践,阐述三大体系的特征、构成和分类,分析三者在静态条件下的优先关系和在动态条件下的互动关系,尝试揭示三大体系之间相互替代、补充、促进、转化和融合的演化规律。 相似文献
8.
9.
本文通过由跳时码唯一确定的编码矩阵将超宽带无线多址通信信道模型建模为一种线性模型,提出了一种新的基于最小二乘准则的超宽带多用户检测算法。该算法把最小二乘准则公式: 写成矩阵形式并且利用矩阵Moore-Penrose逆递推公式实现的自适应递推算法直接对编码矩阵进行更新,从而得到了一种新的超宽带多址通信自适应多用户检测算法。计算机模拟结果表明,该算法比传统的RLS算法有更好的收敛速度,并且相应的自适应多用户检测器比传统的检测器有更好的检测性能。 相似文献
10.
本文综合研究了螺带式搅拌器在假塑性液体中的混合特性及动力特性,测定了双螺带,内外螺带及螺带螺旋3种类型搅拌器的功率常数Kp和Metaner常数Ks,并得出混匀操作和传质工艺过程的放大准则。 相似文献