全文获取类型
收费全文 | 1131篇 |
免费 | 92篇 |
国内免费 | 55篇 |
专业分类
电工技术 | 132篇 |
综合类 | 104篇 |
化学工业 | 113篇 |
金属工艺 | 10篇 |
机械仪表 | 38篇 |
建筑科学 | 98篇 |
矿业工程 | 28篇 |
能源动力 | 35篇 |
轻工业 | 125篇 |
水利工程 | 64篇 |
石油天然气 | 15篇 |
武器工业 | 5篇 |
无线电 | 35篇 |
一般工业技术 | 167篇 |
冶金工业 | 53篇 |
原子能技术 | 5篇 |
自动化技术 | 251篇 |
出版年
2023年 | 12篇 |
2022年 | 21篇 |
2021年 | 23篇 |
2020年 | 29篇 |
2019年 | 26篇 |
2018年 | 34篇 |
2017年 | 33篇 |
2016年 | 36篇 |
2015年 | 38篇 |
2014年 | 55篇 |
2013年 | 85篇 |
2012年 | 72篇 |
2011年 | 99篇 |
2010年 | 53篇 |
2009年 | 72篇 |
2008年 | 63篇 |
2007年 | 90篇 |
2006年 | 82篇 |
2005年 | 66篇 |
2004年 | 44篇 |
2003年 | 37篇 |
2002年 | 35篇 |
2001年 | 28篇 |
2000年 | 19篇 |
1999年 | 15篇 |
1998年 | 20篇 |
1997年 | 8篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1965年 | 1篇 |
1958年 | 1篇 |
1957年 | 3篇 |
1955年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有1278条查询结果,搜索用时 15 毫秒
91.
In developing data‐driven models of complex real‐world systems, a common problem is how to select relevant inputs from a large set of measurements. If the observations of the outputs to be predicted by the model are scarce, which may be the case if the outputs are indices determined in toilsome laboratory tests, strict constraints have to be imposed on the number of model parameters. In neural network modelling, this limitation in practice also restricts the number of hidden nodes as well as the number of input variables, since the dimension of the weight vector strongly depends on these. This paper presents a systematic method for data‐driven modelling with feedforward layered neural networks, including a method for the selection of input variables. The method is illustrated on a problem from ironmaking industry, where sinter quality indices are predicted on the basis of raw material properties. Furthermore, an inversion technique of the resulting network models is proposed, where an optimization problem is solved to maximize the performance of the sintering operation by manipulating the inputs. 相似文献
92.
高校数字化校园评价指标体系的研究 总被引:1,自引:0,他引:1
通过对十多所高校的调查访问,吸取已有的国家信息化和企业信息化的测评理论和方法的优点,提出了一个可行的数字化校园评价指标体系,并对其进行了详细的量化论述.在指标权重的判定中,采用专家打分法来确定每一项指标的权重. 相似文献
93.
多变量自适应极点配置系统稳定的充要条件 总被引:2,自引:0,他引:2
对于多变量自适应极点配置系统给出了其稳定的充要条件,并在充分性的证明过程中构造性地提出了一种估计参数的修正策略,保证了修正参数所对应的广义Sylvester矩阵渐近一致非奇异,得到了无须能控性的稳定多变量自适应极点配置系统,解决了多变量自适应极点配置的奇异问题,所需的先验知识仅为能观性指数和不确定或干扰的上界。 相似文献
94.
本文从服装工效学应用角度,总结了体核温度、体表温度、平均身体温度、新陈代谢产热量、热平衡差、热损失、出汗量、心率和血压等服装生理学评价指标;描述了这些生理指标的测试、计算方法以及有关测试仪器.从而为全面研究服装的舒适性与功能提供了可靠的生理学评价手段. 相似文献
95.
测定了用提拉法生长的优质Li_2B_4O_7晶体的透光曲线,较为准确地测算了该晶体可见光波段的折射率及其Sellmeier方程。 相似文献
96.
Nutritional indices for larch sawfly,Pristiphora erichsonii (Hartig), larvae fed single and tufted needles of fourLarix spp. are reported. Larvae offered only single needles ofL. lancina, L. russica, andL. decidua had lower relative growth rates than larvae fed tufted needles of the same species. There was no significant reduction in larval growth for larvae fedL.
kaempferi single needles as compared to tufted needles. Abietic acid-treated foliage reduced consumption but did not lower relative growth rate. These findings are discussed with respect to the mechanism of preferential feeding of the larch sawfly and current hypotheses of host plant herbivore interaction.Research supported by the School of Natural Resources, College of Agricultural and Life Sciences, University of Wisconsin—Madison under a grant from the McIntire-Stennis Program, Project 2243. 相似文献
97.
Marcel Brun Author Vitae Author Vitae Jianping Hua Author Vitae Author Vitae Brent Carroll Author Vitae Author Vitae Edward R. Dougherty Author Vitae 《Pattern recognition》2007,40(3):807-824
A cluster operator takes a set of data points and partitions the points into clusters (subsets). As with any scientific model, the scientific content of a cluster operator lies in its ability to predict results. This ability is measured by its error rate relative to cluster formation. To estimate the error of a cluster operator, a sample of point sets is generated, the algorithm is applied to each point set and the clusters evaluated relative to the known partition according to the distributions, and then the errors are averaged over the point sets composing the sample. Many validity measures have been proposed for evaluating clustering results based on a single realization of the random-point-set process. In this paper we consider a number of proposed validity measures and we examine how well they correlate with error rates across a number of clustering algorithms and random-point-set models. Validity measures fall broadly into three classes: internal validation is based on calculating properties of the resulting clusters; relative validation is based on comparisons of partitions generated by the same algorithm with different parameters or different subsets of the data; and external validation compares the partition generated by the clustering algorithm and a given partition of the data. To quantify the degree of similarity between the validation indices and the clustering errors, we use Kendall's rank correlation between their values. Our results indicate that, overall, the performance of validity indices is highly variable. For complex models or when a clustering algorithm yields complex clusters, both the internal and relative indices fail to predict the error of the algorithm. Some external indices appear to perform well, whereas others do not. We conclude that one should not put much faith in a validity score unless there is evidence, either in terms of sufficient data for model estimation or prior model knowledge, that a validity measure is well-correlated to the error rate of the clustering algorithm. 相似文献
98.
在实验室条件下,通过在原料混合时添加脱硫剂的方法来脱除烧结烟气中二氧化硫有害气体。分析了烧结烟气中有害气体的危害;介绍了添加脱硫剂的方法;并考察了添加脱硫剂后对烧结技术经济指标的影响。 相似文献
99.
该文依据宿鸭湖水库水质的实际监测资料,采用指数法对水库的水环境进行地表水环境质量评价和水库富营养化评价,采用秩相关系数法对近5年水库水质变化趋势进行分析和评价,提出污染防治对策.结果表明,宿鸭湖水库水质基本满足地表水水域环境功能,水库富营养化程度为轻度富营养化,近5年来水质变化趋势稳定;通过提出针对性的对策和建议,可以进一步降低污染物水平,保障水库综合效益的发挥. 相似文献
100.
TAT软件具有准确、高效的特点,在高层和多层的框架、框架-剪力墙等结构形式的设计中得到了广泛的运用.在结构设计时,TAT的数据接力、参数合理选取和输出信息的正确分析、判断,是保证工程结构设计安全的关键. 相似文献