全文获取类型
收费全文 | 829609篇 |
免费 | 86706篇 |
国内免费 | 55032篇 |
专业分类
电工技术 | 61928篇 |
技术理论 | 91篇 |
综合类 | 90154篇 |
化学工业 | 113646篇 |
金属工艺 | 35639篇 |
机械仪表 | 48795篇 |
建筑科学 | 91203篇 |
矿业工程 | 34976篇 |
能源动力 | 25637篇 |
轻工业 | 54198篇 |
水利工程 | 30670篇 |
石油天然气 | 35030篇 |
武器工业 | 9771篇 |
无线电 | 76488篇 |
一般工业技术 | 76252篇 |
冶金工业 | 38209篇 |
原子能技术 | 9656篇 |
自动化技术 | 139004篇 |
出版年
2024年 | 1508篇 |
2023年 | 10267篇 |
2022年 | 19042篇 |
2021年 | 25455篇 |
2020年 | 24560篇 |
2019年 | 20587篇 |
2018年 | 19717篇 |
2017年 | 25372篇 |
2016年 | 29896篇 |
2015年 | 33400篇 |
2014年 | 50742篇 |
2013年 | 50034篇 |
2012年 | 60381篇 |
2011年 | 64339篇 |
2010年 | 49088篇 |
2009年 | 50044篇 |
2008年 | 48315篇 |
2007年 | 59684篇 |
2006年 | 55277篇 |
2005年 | 47727篇 |
2004年 | 39961篇 |
2003年 | 34289篇 |
2002年 | 27466篇 |
2001年 | 22362篇 |
2000年 | 18324篇 |
1999年 | 14818篇 |
1998年 | 11189篇 |
1997年 | 9616篇 |
1996年 | 8481篇 |
1995年 | 7447篇 |
1994年 | 6389篇 |
1993年 | 4752篇 |
1992年 | 4039篇 |
1991年 | 3021篇 |
1990年 | 2603篇 |
1989年 | 2250篇 |
1988年 | 1651篇 |
1987年 | 1111篇 |
1986年 | 871篇 |
1985年 | 853篇 |
1984年 | 792篇 |
1983年 | 573篇 |
1982年 | 535篇 |
1981年 | 377篇 |
1980年 | 356篇 |
1979年 | 215篇 |
1978年 | 128篇 |
1977年 | 137篇 |
1975年 | 103篇 |
1959年 | 119篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
针对目标估计过程需要大量人工参与、自动化程度低的问题,提出了基于数据质量评价的目标估计方法。利用目标数据质量评价方法,对不同传感器得到的目标数据质量进行科学、有效的测度和评价,并根据质量得分动态调整各数据源在目标估计过程中所占的权重,从而减少人工干预,提高目标估计效能。仿真试验结果证明了该方法的有效性。 相似文献
2.
3.
在单光子计数激光雷达检测领域,目前的检测方法在低信噪比情况下虚警概率会增加,同时也无法适应噪声变化的问题。针对这些问题,提出了一种基于Bayesian的检测方法,该方法首先通过雷达方程估计回波信号光子数的范围,将其作为先验信息,而后结合二项分布建立了累计概率模型,基于Bayesian判决准则计算得到检测阈值,此阈值能够在检测概率与虚警概率中间择其平衡。这种方法不仅克服了低信噪比检测困难的情况,还减少了先验信息的获取难度。实验结果表明,对比固定阈值其虚警概率降低了10倍。对比“恒虚警”其检测概率提高了约20。验证了方法具有良好的检测效果,具备一定的可操作性。 相似文献
4.
Recent generative adversarial networks (GANs) have yielded remarkable performance in face image synthesis. GAN inversion embeds an image into the latent space of a pretrained generator, enabling it to be used for real face manipulation. However, current inversion approaches for real faces suffer the dilemma of initialization collapse and identity loss. In this paper, we propose a hierarchical GAN inversion for real faces with identity preservation based on mutual information maximization. We first use a facial domain guaranteed initialization to avoid the initialization collapse. Furthermore, we prove that maximizing the mutual information between inverted faces and their identities is equivalent to minimizing the distance between identity features from inverted and original faces. Optimization for real face inversion with identity preservation is implemented on this mutual information-maximizing constraint. Extensive experimental results show that our approach outperforms state-of-the-art solutions for inverting and editing real faces, particularly in terms of face identity preservation. 相似文献
5.
为了提高配电网差异化节能降耗效果,解决现有潜力评估方法存在的应用性能差的问题,提出碳中和背景下配电网差异化节能降耗潜力优化评估方法。根据配电网的空间结构,构建相应的等值电路模型。在该模型下,从设备损耗和运行附加损耗2个方面计算配电网的损耗量。根据损耗量计算结果,确定配电网差异化碳中和节能降耗方式。从静态和动态2个角度设置潜力评估指标,通过指标数据处理、指标权重求解等步骤,得出配电网差异化节能降耗潜力的综合量化评估结果。将设计潜力评估方法应用到配电网的差异化节能降耗改造工作中,能够有效降低配电网的实际线损量、降低区域损耗费用,并具有较高的应用价值。 相似文献
6.
《Advanced Powder Technology》2022,33(8):103664
Powder transport systems are ubiquitous in various industries, where they can encounter single powder flow, two-phase flow with solids carried by gas or liquid, and gas–solid–liquid three-phase flow. System geometry, operating conditions, and particle properties have significant impacts on the flow behavior, making it difficult to achieve good transportation of granular materials. Compared to experimental trials and theoretical studies, the numerical approach provides unparalleled advantages over the investigation and prediction of detailed flow behavior, of which the discrete element method (DEM) can precisely capture complex particle-scale information and attract a plethora of research interests. This is the first study to review recent progress in the DEM and coupled DEM with computational fluid dynamics for extensive powder transport systems, including single-particle, gas–solid/solid–liquid, and gas–solid–liquid flows. Some important aspects (i.e., powder electrification during pneumatic conveying, pipe bend erosion, non-spherical particle transport) that have not been well summarized previously are given special attention, as is the application in some new-rising fields (ocean mining, hydraulic fracturing, and gas/oil production). Studies involving important large-scale computation methods, such as the coarse grained DEM, graphical processing unit-based technique, and periodic boundary condition, are also introduced to provide insight for industrial application. This review study conducts a comprehensive survey of the DEM studies in powder transport systems. 相似文献
7.
《Advanced Powder Technology》2022,33(9):103722
Through a facile hydrothermal method, we have successfully prepared Ti3C2/Bi2.15WO6 (TC/BWO) composite, and systematically investigated their reactivity for the photocatalytic reduction of Cr(VI) under visible light. X-ray diffraction and Raman analysis confirm the formation of heterostructure between Bi2.15WO6 and Ti3C2. The resultant 7TC/BWO composite exhibits enhanced photoactivity toward Cr(VI) reduction. After 120 min irradiation, the conversion of Cr(VI) reaches 92.5% with the quasi-first-order kinetic constant of k = 0.0145 min?1, which is higher than that of pure BWO (30% and k = 0.0005 min?1). The electrochemical and photoluminescent characterization confirm that the introduction of Ti3C2 is conducive to the separation of carriers, thus significantly improves the photocatalytic performance of TC/BWO. Furthermore, the radical capture experiments verify that the electrons are important for enhancing reduction of Cr(VI) to Cr(III). As a result, this research provides a comprehensive understanding of the reduction of Cr(VI) by TC/BWO composite under visible light. 相似文献
8.
9.