全文获取类型
收费全文 | 48317篇 |
免费 | 6253篇 |
国内免费 | 3360篇 |
专业分类
电工技术 | 11559篇 |
技术理论 | 2篇 |
综合类 | 3995篇 |
化学工业 | 3161篇 |
金属工艺 | 1994篇 |
机械仪表 | 2035篇 |
建筑科学 | 5413篇 |
矿业工程 | 1762篇 |
能源动力 | 981篇 |
轻工业 | 1432篇 |
水利工程 | 1946篇 |
石油天然气 | 2196篇 |
武器工业 | 391篇 |
无线电 | 5803篇 |
一般工业技术 | 2535篇 |
冶金工业 | 1492篇 |
原子能技术 | 464篇 |
自动化技术 | 10769篇 |
出版年
2024年 | 248篇 |
2023年 | 626篇 |
2022年 | 1306篇 |
2021年 | 1651篇 |
2020年 | 1634篇 |
2019年 | 1209篇 |
2018年 | 1104篇 |
2017年 | 1440篇 |
2016年 | 1561篇 |
2015年 | 1915篇 |
2014年 | 3663篇 |
2013年 | 2632篇 |
2012年 | 3906篇 |
2011年 | 4232篇 |
2010年 | 3266篇 |
2009年 | 3297篇 |
2008年 | 3087篇 |
2007年 | 3580篇 |
2006年 | 3239篇 |
2005年 | 2655篇 |
2004年 | 2143篇 |
2003年 | 2005篇 |
2002年 | 1584篇 |
2001年 | 1377篇 |
2000年 | 1115篇 |
1999年 | 842篇 |
1998年 | 588篇 |
1997年 | 428篇 |
1996年 | 373篇 |
1995年 | 297篇 |
1994年 | 207篇 |
1993年 | 143篇 |
1992年 | 97篇 |
1991年 | 72篇 |
1990年 | 64篇 |
1989年 | 56篇 |
1988年 | 54篇 |
1987年 | 21篇 |
1986年 | 33篇 |
1985年 | 27篇 |
1984年 | 37篇 |
1983年 | 23篇 |
1982年 | 23篇 |
1981年 | 22篇 |
1980年 | 15篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1975年 | 3篇 |
1973年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Massive Open Online Courses (MOOCs) are becoming an essential source of information for both students and teachers. Noticeably, MOOCs have to adapt to the fast development of new technologies; they also have to satisfy the current generation of online students. The current MOOCs’ Management Systems, such as Coursera, Udacity, edX, etc., use content management platforms where content are organized in a hierarchical structure. We envision a new generation of MOOCs that support interpretability with formal semantics by using the SemanticWeb and the online social networks. Semantic technologies support more flexible information management than that offered by the current MOOCs’ platforms. Annotated information about courses, video lectures, assignments, students, teachers, etc., can be composed from heterogeneous sources, including contributions from the communities in the forum space. These annotations, combined with legacy data, build foundations for more efficient information discovery in MOOCs’ platforms. In this article we review various Collaborative Semantic Filtering technologies for building Semantic MOOCs’ management system, then, we present a prototype of a semantic middle-sized platform implemented at Western Kentucky University that answers these aforementioned requirements. 相似文献
3.
4.
Rectangular section control technology(RSCT)was introduced to achieve high-precision profile control during silicon steel rolling.The RSCT principle and method were designed,and the whole RSCT control strategy was developed.Specifically,RSCT included roll contour design,rolling technology optimization,and control strategy development,aiming at both hot strip mills(HSMs)and cold strip mills(CSMs).Firstly,through the high-performance variable crown(HVC)work roll optimization design in the upper-stream stands and the limited shifting technology for schedule-free rolling in the downstream stands of HSMs,a hot strip with a stable crown and limited wedge,local spot,and single wave was obtained,which was suitable for cold rolling.Secondly,an approximately rectangular section was obtained by edge varying contact(EVC)work roll contour design,edge-drop setting control,and closed loop control in the upper-stream stands of CSMs.Moreover,complex-mode flatness control was realized by coordinating multiple shape-control methods in the downstream stands of CSMs.In addition,the RSCT approach was applied in several silicon-steel production plants,where an outstanding performance and remarkable economic benefits were observed. 相似文献
5.
文章通过对黑龙江省高效节水现状,存在问题的分析,结合黑龙江省高效节水发展的支撑能力,阐述黑龙江省节水增粮目标、任务及总体布局,为黑龙江省2012—2015年节水增粮实施提供依据。 相似文献
6.
从电焊机自身电气特点及建筑工地工作环境入手,探讨电焊机安全技术的实施方法。分析电焊机安全隐患及事故的分类以及电焊机在使用过程中产生危险的原因。介绍电焊机在安装以及作业过程中的安全措施。 相似文献
8.
Innumerable casualties due to intrauterine hypoxia are a major worry during prenatal phase besides advanced patient monitoring with latest science and technology. Hence, the analysis of foetal electrocardiogram (fECG) signals is very vital in order to evaluate the foetal heart status for timely recognition of cardiac abnormalities. Regrettably, the latest technology in the cutting edge field of biomedical signal processing does not seem to yield the desired quality of fECG signals required by physicians, which is the major cause for the pathetic condition. The focus of this work is to extort non-invasive fECG signal with highest possible quality with a motive to support physicians in utilizing the methodology for the latest intrapartum monitoring technique called STAN (ST analysis) for forecasting intrapartum foetal hypoxia. However, the critical quandary is that the non-invasive fECG signals recorded from the maternal abdomen are affected by several interferences like power line interference, baseline drift interference, electrode motion interference, muscle movement interference and the maternal electrocardiogram (mECG) being the dominant interference. A novel hybrid methodology called BANFIS (Bayesian adaptive neuro fuzzy inference system) is proposed. The BANFIS includes a Bayesian filter and an adaptive neuro fuzzy filter for mECG elimination and non-linear artefacts removal to yield high quality fECG signal. Kalman filtering frame work has been utilized to estimate the nonlinear transformed mECG component in the abdominal electrocardiogram (aECG). The adaptive neuro fuzzy filter is employed to discover the nonlinearity of the nonlinear transformed version of mECG and to align the estimated mECG signal with the maternal component in the aECG signal for annulment. The outcomes of the investigation by the proposed BANFIS system proved valuable for STAN system for efficient prediction of foetal hypoxia. 相似文献
9.
A double optimal projection method that involves projections for intra-cluster and inter-cluster dimensionality reduction are proposed for video fingerprinting. The video is initially set as a graph with frames as its vertices in a high-dimensional space. A similarity measure that can compute the weights of the edges is then proposed. Subsequently, the video frames are partitioned into different clusters based on the graph model. Double optimal projection is used to explore the optimal mapping points in a low-dimensional space to reduce the video dimensions. The statistics and geometrical fingerprints are generated to determine whether a query video is copied from one of the videos in the database. During matching, the video can be roughly matched by utilizing the statistics fingerprint. Further matching is thereafter performed in the corresponding group using geometrical fingerprints. Experimental results show the good performance of the proposed video fingerprinting method in robustness and discrimination. 相似文献
10.