全文获取类型
收费全文 | 108180篇 |
免费 | 12034篇 |
国内免费 | 7789篇 |
学科分类
工业技术 | 128003篇 |
出版年
2024年 | 444篇 |
2023年 | 1759篇 |
2022年 | 3903篇 |
2021年 | 5012篇 |
2020年 | 3762篇 |
2019年 | 2791篇 |
2018年 | 2919篇 |
2017年 | 3188篇 |
2016年 | 2971篇 |
2015年 | 4600篇 |
2014年 | 6041篇 |
2013年 | 6951篇 |
2012年 | 8414篇 |
2011年 | 9126篇 |
2010年 | 8703篇 |
2009年 | 8463篇 |
2008年 | 8522篇 |
2007年 | 8088篇 |
2006年 | 7199篇 |
2005年 | 5871篇 |
2004年 | 4243篇 |
2003年 | 3062篇 |
2002年 | 3021篇 |
2001年 | 2738篇 |
2000年 | 2063篇 |
1999年 | 1142篇 |
1998年 | 594篇 |
1997年 | 464篇 |
1996年 | 434篇 |
1995年 | 355篇 |
1994年 | 229篇 |
1993年 | 182篇 |
1992年 | 136篇 |
1991年 | 114篇 |
1990年 | 84篇 |
1989年 | 86篇 |
1988年 | 68篇 |
1987年 | 41篇 |
1986年 | 40篇 |
1985年 | 19篇 |
1984年 | 16篇 |
1983年 | 21篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 28篇 |
1979年 | 18篇 |
1976年 | 4篇 |
1965年 | 2篇 |
1959年 | 11篇 |
1951年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
随着大数据和云计算的技术的深入应用,人工智能时代的机器学习和深度学习更需要日益增长的数据,因此数据安全与隐私保护变得更加迫切。本文介绍人工智能的定义以及特征,探究数据安全和隐私保护现状,分析数据安全和隐私保护面临的诸多问题,并提出在人工智能时代对数据安全和隐私保护的措施。 相似文献
42.
Qiang Xia Tao Feng Xiaowei Lou Ying Wang Yangying Sun Daodong Pan Jinxuan Cao 《International Journal of Food Science & Technology》2020,55(2):669-680
As a decisive attribute, flavour could be influenced by HP treatments through multiple physical and chemical pathways within the high pressure (HP)-assisted meat curing process. This investigation aimed to identify the major pathway influencing volatile flavour patterns of two representative vinasse-cured duck (VCD) products with HP treatments (150–300 MPa/15 min), including wet and dry types, by employing headspace fingerprinting as an untargeted approach. Results suggested that HP treatments greatly lowered moisture contents and increased Warner-Bratzler shear force and thiobarbituric acid reactive substances of the cured samples. According to multivariate models, the volatile flavour patterns of the HP-processed VCD could be clearly separated from the unprocessed samples, but the VCD pressurised at different intensities represented similar volatile fingerprinting, which was validated by e-nose analysis. The discriminant analysis (OPLS-DA) model outlined vinasse-derived ethanol, acetic acid, 3-methyl-1-butanol, 2-methyl-1-butanol, phenethyl alcohol and 2-methyl-3-octanone as the major discriminant aromas across the unpressurised and pressurised samples. 相似文献
43.
The application of deep learning in the field of object detection has
experienced much progress. However, due to the domain shift problem, applying an
off-the-shelf detector to another domain leads to a significant performance drop. A
large number of ground truth labels are required when using another domain to train
models, demanding a large amount of human and financial resources. In order to avoid
excessive resource requirements and performance drop caused by domain shift, this
paper proposes a new domain adaptive approach to cross-domain vehicle detection. Our
approach improves the cross-domain vehicle detection model from image space and
feature space. We employ objectives of the generative adversarial network and cycle
consistency loss for image style transfer in image space. For feature space, we align
feature distributions between the source domain and the target domain to improve the
detection accuracy. Experiments are carried out using the method with two different
datasets, proving that this technique effectively improves the accuracy of vehicle
detection in the target domain. 相似文献
44.
45.
Wang Lu-di Zhou Wei Xing Ying Liu Na Movahedipour Mahmood Zhou Xiao-guang 《浙江大学学报:C卷英文版》2019,20(3):405-413
Frontiers of Information Technology & Electronic Engineering - Reconstruction of a 12-lead electrocardiogram (ECG) from a serial 3-lead ECG has been researched in the past to satisfy the need... 相似文献
46.
47.
User Modeling and User-Adapted Interaction - Personality plays a pivotal role at work. Many scholars have investigated the association between personality and language usage habits in the English... 相似文献
48.
Xiangrong Ma Rui Dang Ning Yang Xiao Li Ya zhang Ying Gong Zhipan Liu Wei Guo Yuanyuan Zhang Chunyan Li 《International Journal of Hydrogen Energy》2021,46(44):22842-22851
The high cost of noble metal catalysts has been a great bottleneck for the catalyst industry. Using the noble metal at a single-atom level for catalytic applications could dramatically decrease the cost. The impacts of single Pt atoms on the photocatalytic performance of Ag3VO4 have been investigated and reported. In this report, single Pt atoms were anchored on the surface of Ag3VO4 (AVO) as a cocatalyst, and the resultant composite photocatalyst has been studied for photocatalytic H2 production from water driven by visible light. The as-prepared AVO particles are hollow nanospheres in the monoclinic phase with a bandgap of 2.20 eV. The light absorption edge of AVO/Pt is slightly red-shifted compared to that of the pristine AVO, indicating more visible light absorption of AVO/Pt. The XPS peaks of Ag, V, and Pt exhibit a significant shift after AVO and Pt get into contact, suggesting the strong interaction between the surface Ag and V atoms, and single Pt atoms. After 3-h illumination, the photocatalytic H2 evolution amount from AVO/Pt is improved up to 1400 μmol, which is 2.8 times that on the bare AVO. Such efficient photocatalytic H2 evolution on AVO/Pt is still maintained after five reaction cycles. The better photocatalytic performance of AVO/Pt has been attributed to the more efficient visible light utilization and the lower interfacial charge transfer resistance, as demonstrated in the DRS and EIS spectra. The presence of the surface Pt atoms also leads to a higher amount of reactive radicals, which could efficiently promote the surface redox reactions. 相似文献
49.
以视平线可与显示器中心重合为准,分别探讨显示器中心在视平线上方、下方时不同视距对头部关节舒适度的影响. 实验自变量为视距(眼睛与显示器中心的水平距离),因变量为头部关节舒适度. 实验结果显示:1)显示器中心在人视平线上方时,头部舒适性状态始终处于不舒适状态,此时视距与人的头部舒适性关系成正比,即视距越大,头部舒适性越好;2)显示器中心在人视平线下方时,头部关节舒适状态始终处于正常范围,舒适性程度随视距增大而减小. 相似文献
50.
如何在海量不确定数据集中提高频繁模式挖掘性能是目前研究的热点.传统算法大多是以期望、概率或者权重等单一指标为数据项集支持度,在大数据背景下,同时考虑概率和权重支持度的算法难以兼顾其执行效率.为此,本文提出一种基于Spark的不确定数据集频繁模式挖掘算法(UWEFP),首先,为了同时兼顾数据项的概率和权重,计算一项集的最大概率权重值并进行剪枝;然后,为了减少对数据集的多次扫描,结合Spark框架的优点,设计了一种具有FP-tree特征的新颖的UWEFP-tree结构进行模式树的构建及挖掘;最后在Spark环境下,以UCI数据集进行实验验证.实验结果表明本文的方法在保证挖掘结果的同时,提高了效率. 相似文献