全文获取类型
收费全文 | 489523篇 |
免费 | 53566篇 |
国内免费 | 35996篇 |
专业分类
电工技术 | 42729篇 |
技术理论 | 53篇 |
综合类 | 53194篇 |
化学工业 | 42957篇 |
金属工艺 | 15728篇 |
机械仪表 | 27079篇 |
建筑科学 | 41019篇 |
矿业工程 | 14444篇 |
能源动力 | 13899篇 |
轻工业 | 20603篇 |
水利工程 | 18354篇 |
石油天然气 | 19681篇 |
武器工业 | 5180篇 |
无线电 | 54687篇 |
一般工业技术 | 40206篇 |
冶金工业 | 17047篇 |
原子能技术 | 5399篇 |
自动化技术 | 146826篇 |
出版年
2024年 | 951篇 |
2023年 | 6245篇 |
2022年 | 12194篇 |
2021年 | 15671篇 |
2020年 | 14998篇 |
2019年 | 12028篇 |
2018年 | 11530篇 |
2017年 | 14242篇 |
2016年 | 17325篇 |
2015年 | 19814篇 |
2014年 | 31820篇 |
2013年 | 30595篇 |
2012年 | 33358篇 |
2011年 | 35308篇 |
2010年 | 28097篇 |
2009年 | 30368篇 |
2008年 | 31054篇 |
2007年 | 36115篇 |
2006年 | 31768篇 |
2005年 | 27526篇 |
2004年 | 22515篇 |
2003年 | 20286篇 |
2002年 | 16398篇 |
2001年 | 12818篇 |
2000年 | 11189篇 |
1999年 | 9032篇 |
1998年 | 6988篇 |
1997年 | 6014篇 |
1996年 | 5675篇 |
1995年 | 5256篇 |
1994年 | 4482篇 |
1993年 | 2989篇 |
1992年 | 2623篇 |
1991年 | 1945篇 |
1990年 | 1502篇 |
1989年 | 1334篇 |
1988年 | 1092篇 |
1987年 | 652篇 |
1986年 | 525篇 |
1985年 | 690篇 |
1984年 | 713篇 |
1983年 | 669篇 |
1982年 | 528篇 |
1981年 | 523篇 |
1980年 | 389篇 |
1979年 | 223篇 |
1978年 | 153篇 |
1977年 | 116篇 |
1975年 | 77篇 |
1962年 | 77篇 |
排序方式: 共有10000条查询结果,搜索用时 125 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.
针对目前大多数人脸识别算法参数多、计算量大,难以部署到移动端和嵌入式设备中的问题,提出了一种基于改进MobileFaceNet的人脸识别方法。通过对MobileFaceNet模型结构的调整,将bottleneck模块优化为sandglass模块,改良深度卷积和逐点卷积的相对位置,适当增大sandglass模块的输出通道数,从而减少特征压缩时的信息丢失,增强人脸空间特征的提取。实验结果表明:改进后的方法在LFW测试数据集上准确率达99.15%,模型大小和计算量分别仅为原算法的61%和45%,验证了所提方法的有效性。 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.
Sandstorm is a meteorological phenomenon common in arid and semi-arid regions. A sandstorm can carry large volumes of sand unexpectedly, which leads to severe color deviations and significantly degraded visibility when an image is taken in such a scenario. However, existing image enhancement methods cannot enhance sandstorm images well due to the challenging degradations and the scarcity of sandstorm training data. In this paper, we propose a Transformer with rotary position embedding to perform sandstorm image enhancement via building multi-scale and multi-patch dependencies. Our key insights in this work are 1) a multi-scale Transformer can globally eliminate the color deviations of sandstorm images via aggregating global information, 2) a multi-patch Transformer can recover local details well via learning the spatial variant degradations, and 3) a U-shape Transformer with rotary position embedding as the core unit of multi-scale and multi-patch Transformer can effectively build the long-range dependencies. We also contribute a real-world Sandstorm Image Enhancement (SIE) dataset including 1,400 sandstorm images with different degrees of degradations and various scenes. Experiments performed on synthetic images and real-world sandstorm images demonstrate that our proposed method not only obtains visually pleasing results but also outperforms state-of-the-art methods qualitatively and quantitatively. 相似文献
6.
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
7.
8.
An analytical model for gas leakage through contact interface in proton exchange membrane fuel cells
《International Journal of Hydrogen Energy》2022,47(75):32273-32286
Sealing performance between two contacting surfaces is of significant importance to stable operation of proton exchange membrane (PEM) fuel cells. In this work, an analytical micro-scale approach is first established to predict the gas leakage in fuel cells. Gas pressure and uneven pressure distribution at the interface are also included in the model. At first, the micro tortuous leakage path at the interface is constructed by introducing contact modelling and fractal porous structure theory. In order to obtain the leakage at the entire surface, contact pressure distribution is predicted based on bonded elastic layer model. The gas leakage through the discontinuous interface can be obtained with consideration of convection and diffusion. Then, experiments are conducted to validate the numerical model, and good agreement is obtained between them. Finally, influences of surface topology, gasket compression and gasket width on leakage are studied based on the model. The results show that gas leakage would be greatly amplified when the asperity standard deviation of surface roughness exceeds 1.0 μm. Gaskets with larger width and smaller thickness are beneficial to sealing performance. The model is helpful to understand the gas leakage behavior at the interface and guide the gasket design of fuel cells. 相似文献
9.
《International Journal of Hydrogen Energy》2022,47(85):36216-36231
The fuel cell/battery durability and hybrid system stability are major considerations for the power management of fuel cell hybrid electric bus (FCHEB) operating on complicated driving conditions. In this paper, a real time nonlinear adaptive control (NAC) with stability analyze is formulated for power management of FCHEB. Firstly, the mathematical model of hybrid power system is analyzed, which is established for control-oriented design. Furthermore, the NAC-based strategy with quadratic Lyapunov function is set up to guarantee the stability of closed-loop power system, and the power split between fuel cell and battery is controlled with the durability consideration. Finally, two real-time power management strategies, state machine control (SMC) and fuzzy logic control (FLC), are implemented to evaluate the performance of NAC-based strategy, and the simulation results suggest that the guaranteed stability of NAC-based strategy can efficiently prolong fuel cell/battery lifespan and provide better fuel consumption economy for FCHEB. 相似文献
10.
《International Journal of Hydrogen Energy》2022,47(62):26435-26457
In this study, some locations with different climates, off-grid zero energy buildings with hydrogen energy storage systems are designed, and transient analysis is conducted. These considered buildings supply their electricity consumption without using the electrical grid and PV panels or wind turbines. Also, they supply thermal comfort to occupants by using a vapor compression chiller and humidifier. Domestic hot water of occupants is supplied using solar collectors. For analyzing building's performance and objectives achievement, TRNSYS software is used. Also, for evaluating occupant thermal comfort, the Fanger model is used. The considered building is a one-story building with a 150 m2 area. Four occupants are considered. Both of them are seated at rest, and another is seated with light working such as typing. Using the Fanger model equation and MATLAB software, the thermal comfort of occupants is determined. For domestic hot water consumption, verified profiles that vary during 24 h of the day are considered. Achieved results show that for humid and cold cities, PV panels with an area of 73 and 76 m2 can be supplied the required electricity of considered building with four occupants and battery state of charge is higher than 50% and 10%, respectively. Moreover, with a suitable air conditioner system, the predicted percentage of dissatisfied (PPD) can be lower than 12% and 8% for humid and cold cities. Therefore, the building can be converted to a zero-energy building using its rooftop area. 相似文献