全文获取类型
收费全文 | 12184篇 |
免费 | 2633篇 |
国内免费 | 1836篇 |
学科分类
工业技术 | 16653篇 |
出版年
2024年 | 186篇 |
2023年 | 702篇 |
2022年 | 666篇 |
2021年 | 784篇 |
2020年 | 740篇 |
2019年 | 726篇 |
2018年 | 355篇 |
2017年 | 492篇 |
2016年 | 512篇 |
2015年 | 568篇 |
2014年 | 828篇 |
2013年 | 742篇 |
2012年 | 921篇 |
2011年 | 975篇 |
2010年 | 955篇 |
2009年 | 940篇 |
2008年 | 989篇 |
2007年 | 910篇 |
2006年 | 732篇 |
2005年 | 661篇 |
2004年 | 519篇 |
2003年 | 434篇 |
2002年 | 299篇 |
2001年 | 223篇 |
2000年 | 182篇 |
1999年 | 141篇 |
1998年 | 129篇 |
1997年 | 65篇 |
1996年 | 65篇 |
1995年 | 53篇 |
1994年 | 38篇 |
1993年 | 13篇 |
1992年 | 29篇 |
1991年 | 23篇 |
1990年 | 23篇 |
1989年 | 19篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 245 毫秒
51.
52.
53.
54.
The Miao nationality is the sixth largest ethnic group in China which has a history of thousands of years. It has created a unique material culture and spiritual culture in its development process and the Miao costume is a highly condensed collection of the material and spiritual culture of the Miao nationality. As one of the unique symbols of Miao culture the Miao costume has profound cultural heritage and cultural connotations. The patterns of the Miao costume are particularly eye-catching as they not only symbolize the wisdom of the Miao people in thousands of years of production and life but also symbolize the pursuit of the good spirit of the Miao people. However under the impact of modern pop culture and foreign culture these cultural symbols are gradually disappearing. In order to protect and inherit them the Miao costume pattern segmentation has become the most important work. However the Miao costume pattern segmentation is quite difficult. At present there are few studies on the extraction classification identification and preservation of the features of Miao costume pattern segmentation. With the excellent segmentation performance of the U-Net model and the advantages of easy deployment the paper improves the basic structure of the U-Net model and proposes a Miao costume pattern segmentation algorithm based on the RSKP-UNet Residual Selective-Kernel Parallel U-Net model. The algorithm adds Residual modules in the encoder part of the U-Net model to improve the feature extraction capability of the model and embeds the SKNet modules and ParNet modules in the decoder part to enhance the feature expression capability of the model. The paper uses evaluation metrics to measure the segmentation performance of the model and compares it with four segmentation models based on deep learning. The paper not only combines the current research focus-deep learning and attention mechanism but also introduces the Lovász-hinge loss function to effectively solve the problem of class imbalance in the Miao costume patterns. The RSKP-UNet model is better than other models in various segmentation indicators. Compared with the benchmark model U-Net the Dice coefficient IoU precision recall and accuracy are improved by 6. 98% 11. 07% 2. 89% 6. 75% and 3. 92% . The segmentation algorithm proposed in this paper realizes the extraction of the element content of the Miao costume patterns through image segmentation of Miao costume patterns which can be used to build the Miao costume pattern database in this way thus helping designers relevant researchers and organizations to provide research foundation and completing the protection and inheritance of the Miao costume culture. The paper also provides some reference for the segmentation research of other minority costume patterns. © 2022 Authors. All rights reserved. 相似文献
55.
56.
为了满足水库漂浮物强监管的需求,发挥水库水雨情视频监控的优势,将语义分割算法DeepLabV3+应用于水库漂浮物智能识别任务中。首先,通过多要素数据采集方法以及多种图像数据增强方式系统性整合得到水库漂浮物语义分割数据集。然后,提出改进的加权代价函数,以适应数据集中各类的总像素数量不平衡的问题。实验结果表明,通过规范采集与多种数据增强建立的数据集,以及改进的加权代价函数,提高了水库漂浮物语义分割模型的准确率。所提模型像素准确率平均值、平均交叉比分别可达到95.21%、91.03%,通过微信企业号实现的移动监管,可为水利相关部门对水库漂浮物进行及时的智能监控预警提供新的技术方案。 相似文献
57.
58.
介绍了利用GPS RTK配合全站仪及在控制点上放出转站,进行地形复杂地段横断面测量的技术方法,讨论了其观测数据、资料处理的有关问题。 相似文献
59.
主要介绍应用MAPGIS制图过程中,使用结点平差操作所产生的误差,如:改变了原线段的方向,区分割时。使弧段产生变形,从而使结点平差后的弧段,分割后的区的属性未接要求进行改变,并提出了消除这些误差的方法与建议。 相似文献
60.