全文获取类型
收费全文 | 66823篇 |
免费 | 8823篇 |
国内免费 | 7005篇 |
专业分类
电工技术 | 5888篇 |
技术理论 | 9篇 |
综合类 | 7233篇 |
化学工业 | 1563篇 |
金属工艺 | 798篇 |
机械仪表 | 4143篇 |
建筑科学 | 2350篇 |
矿业工程 | 1657篇 |
能源动力 | 829篇 |
轻工业 | 814篇 |
水利工程 | 1427篇 |
石油天然气 | 3174篇 |
武器工业 | 975篇 |
无线电 | 11134篇 |
一般工业技术 | 3295篇 |
冶金工业 | 1198篇 |
原子能技术 | 769篇 |
自动化技术 | 35395篇 |
出版年
2024年 | 370篇 |
2023年 | 978篇 |
2022年 | 1962篇 |
2021年 | 2470篇 |
2020年 | 2678篇 |
2019年 | 2082篇 |
2018年 | 1901篇 |
2017年 | 2352篇 |
2016年 | 2614篇 |
2015年 | 3003篇 |
2014年 | 4656篇 |
2013年 | 4182篇 |
2012年 | 5001篇 |
2011年 | 5354篇 |
2010年 | 4128篇 |
2009年 | 4075篇 |
2008年 | 4579篇 |
2007年 | 5167篇 |
2006年 | 4335篇 |
2005年 | 3819篇 |
2004年 | 3267篇 |
2003年 | 2785篇 |
2002年 | 2113篇 |
2001年 | 1656篇 |
2000年 | 1384篇 |
1999年 | 1015篇 |
1998年 | 806篇 |
1997年 | 686篇 |
1996年 | 568篇 |
1995年 | 486篇 |
1994年 | 395篇 |
1993年 | 300篇 |
1992年 | 206篇 |
1991年 | 201篇 |
1990年 | 148篇 |
1989年 | 125篇 |
1988年 | 95篇 |
1987年 | 72篇 |
1986年 | 72篇 |
1985年 | 94篇 |
1984年 | 69篇 |
1983年 | 84篇 |
1982年 | 74篇 |
1981年 | 48篇 |
1980年 | 30篇 |
1979年 | 41篇 |
1978年 | 16篇 |
1977年 | 25篇 |
1976年 | 13篇 |
1959年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
本文以云杉八齿小蠹Ips typographus Linnaeus为例,经标本选取,观察虫体整体形态,绘制整体结构草图,电子显微镜观察局部、得到局部数字图像,分别建立虫体每一部分的高精度细节。把模型每部分拼装在一起组成整体模型,构建出了云杉八齿小蠹三维虚拟昆虫数字化模型。 相似文献
3.
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
4.
7.
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
8.
An engineered variant of the yeast Pichia pastoris was used to produce the potential malaria vaccine D1M1. This paper describes the implementation of an expanded bed adsorption chromatography step into a sequential cultivation process of the yeast in order to link protein expression, cell release, and product capture of the secreted protein in a fully automated plant. The process is operated with a semi-continuous strategy for an integrated production. Process improvements have been achieved using design of experiments. Resulting purities of product achieved up to 87% with recoveries of 51% in a single downstream operation. Furthermore, a multivariate analysis of historical batch data was used to develop a golden batch model for process monitoring. 相似文献
9.
10.
大坝运行监测易受自然环境和监测条件影响,存在时间和空间上的变异性,监测数据具有不确定性。以云理论的随机性和不确定性分析方法为基础,并与空间数据辐射思想相结合,建立了云滴概率密度分布估计模型,然后导出云概率密度分布函数,依据样本监测数据推求母体空间数据的分布特征,并设计了基于逆向云算法云变换的计算程序。分析陆浑水库1979~1999年测压管监测数据和位移变形数据的云概率密度分布特征和云数字特征,得出了20 a来大坝的数据分布特征和运行状态。监测数据分析结果表明,云概率密度分布估计不仅能有效合理地分析大坝的运行状态,而且能够依据云数字特征来判断监测状态和监测环境的异常变化。
相似文献