首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   363篇
  免费   24篇
电工技术   7篇
化学工业   70篇
金属工艺   10篇
机械仪表   11篇
建筑科学   10篇
能源动力   24篇
轻工业   64篇
水利工程   5篇
无线电   29篇
一般工业技术   68篇
冶金工业   43篇
原子能技术   4篇
自动化技术   42篇
  2024年   2篇
  2023年   6篇
  2022年   12篇
  2021年   11篇
  2020年   13篇
  2019年   14篇
  2018年   9篇
  2017年   19篇
  2016年   18篇
  2015年   14篇
  2014年   14篇
  2013年   44篇
  2012年   15篇
  2011年   26篇
  2010年   20篇
  2009年   14篇
  2008年   16篇
  2007年   19篇
  2006年   11篇
  2005年   5篇
  2004年   8篇
  2003年   5篇
  2002年   10篇
  2001年   5篇
  2000年   10篇
  1999年   7篇
  1998年   5篇
  1997年   10篇
  1996年   5篇
  1995年   8篇
  1994年   3篇
  1990年   2篇
  1988年   2篇
  1987年   1篇
  1985年   1篇
  1982年   1篇
  1980年   2篇
排序方式: 共有387条查询结果,搜索用时 0 毫秒
71.
International Journal on Software Tools for Technology Transfer - We introduce in this paper $$\text {AMT} \; 2.0$$ , a tool for qualitative and quantitative analysis of hybrid continuous and...  相似文献   
72.
This study develops a geothermal-based underground pumped hydroenergy storage system (UPHES) integrated with an organic Rankine cycle (ORC) and district heating. The ORC has been integrated into the system for contributing the power demand of the pump used during the charging period to pump the water from the underground to the upper reservoir. District heating has been performed by geothermal. Heat recovered from the ORC has been used for the preheating of water used in district heating before entering the upper reservoir. With this proposed integrated system, both the peak energy demand has been shifted to off-peak hours and district heating has been performed. An ORC has also been included in the system to contribute to the energy demand of the UPHES pump. In order to evaluate the system's performance, thermodynamic analysis has been performed base on energetic and exergetic efficiencies. In the base case study, 60 MWh of electricity has stored by the UPHES. Also, a 2.8 MW of heating demand of 100 houses has been met and a 1.7 MW of power has been generated by the ORC. The power of the UPHES pump has been calculated as 6.81 MW. The efficiency of the UPHES system is 73.34%. Overall energy and exergy efficiencies of the proposed integrated system have been calculated as 93.09% and 78.37%, respectively.  相似文献   
73.
Kaya  Dogan  Cobley  Richard J.  Palmer  Richard E. 《Nano Research》2020,13(1):145-150
Nano Research - Understanding the atomistic formation of oxide layers on semiconductors is important for thin film fabrication, scaling down conventional devices and for the integration of emerging...  相似文献   
74.
75.
Single-pellet moment technique was used for the evaluation of effective diffusivities and adsorption equilibrium constants of hydrogen, carbon dioxide, and helium in pure alumina and palladium-impregnated alumina pellets. It was found that hydrogen was strongly adsorbed on palladium of Pd-alumina pellets, and significant enhancement of hydrogen diffusivity was observed due to impregnated palladium at 40°C. On the other hand, for carbon dioxide and helium, effective diffusivities obtained in Pd-alumina pellets were smaller than the corresponding values in pure alumina due to higher tortuosity factor values of Pd-alumina pellets.  相似文献   
76.
Analysis and Design of RF CMOS Attenuators   总被引:1,自引:0,他引:1  
Attenuators are analyzed for their minimum Insertion Loss (IL), maximum attenuation and source-load matching performance. These results are used to make trade-offs in the design of a CMOS attenuator with wide dynamic range, designed and fabricated in a 0.13 mum CMOS process. The design employs two non-identical cascaded T-stages that are activated consecutively to improve linearity. The design operates in the frequency band of DC-2.5 GHz with 0.9-3.5 dB insertion loss and 42 dB maximum attenuation in the entire frequency range. Worst case S11 is - 8.2 dB across the frequency band. The design achieves an IIP3 of + 20 dBm at mid-attenuation.  相似文献   
77.
The Southeastern Anatolia Project (GAP), which was initiated in 1976 as a large-scale and multisectoral regional development project in Turkey, is a combination of 13 projects primarily for hydropower generation and irrigation. The project involves the construction of 22 dams and 19 hydroelectric plants with a total capacity of 7500 MW. At full development 27.3 billion kWhr of hydroelectric energy will be generated annually. GAP will also provide irrigation for 1.7 million ha of land corresponding to one-fifth of irrigable land of Turkey. As an integrated development project relating sectors including hydropower,irrigation, industry, transportation and social infrastructure, the Southeastern Anatolia Project has top priority among national projects of Turkey. In this paper, various aspects of hydropower and irrigation planning and development for the Southeastern Anatolia project will be discussed. Water availability, agricultural and other objectives, physical structures, developmentstrategies and scenarios are examined. Some important aspects of international water use are discussed.  相似文献   
78.
The spectral response of back-surface-illuminated p-GaN-i-GaN/AlGaN multiplequantum well (MQW)-n-AlGaN ultraviolet (UV) photodetector is reported. The structure was grown by molecular-beam epitaxy on a c-plane sapphire substrate. A MQW is introduced into the active region of the device to enhance the quantum efficiency caused by the high absorption coefficient of the two-dimensional (2-D) system. Another advantage of using MQW in the active region is the ability to tune the cutoff wavelength of the photodetector by adjusting the well width, well composition, and barrier height. The zero-bias peak responsivity was found to be 0.095 A/W at 330 nm, which corresponds to 36% quantum efficiency from as-grown p-i-n GaN/AlGaN MQW devices. An anomalous effect, occurring in responsivity as a negative photoresponse in the spectra peaked at 362 nm because of poor ohmic contact to p-type GaN, was also observed. Etching the sample in KOH for 30 sec before fabrication removed the surface contaminants and improved the surface smoothness of the as-grown sample, resulting in significant improvement in the device performance, giving a peak responsivity of 0.12 A/W. The device has a quantum efficiency of 45% at 330 nm without the anomalous negative photocurrent.  相似文献   
79.
The tendency for gastric mucosa-associated lymphoid tissue (MALT) lymphoma cells preferentially to localize around reactive B-cell follicles, both in the mucosa and regional lymph nodes, coupled with their immunophenotype, has led to the proposal that the normal cell counterpart of this lymphoma is the marginal zone B cell. In keeping with this proposition, lymphocytes expressing the lymphoma idiotype have been detected in the splenic marginal zone in a single case of gastric MALT lymphoma. To confirm that this truly represented preferential homing of MALT lymphoma to the splenic marginal zone, we have now re-examined this case, together with 17 other cases, using both immunohistochemical and molecular methods in an attempt to establish clonal identity between the gastric lymphoma and cells in the splenic marginal zone. In three cases, the spleen was characterized by marked expansion of marginal zones by cells showing the same pattern of Ig light chain restriction as the gastric lymphoma. None of the remaining 15 cases showed histologic evidence of lymphomatous infiltration. Analysis of the Ig genes by polymerase chain reaction (PCR), cloning, and sequencing confirmed clonal identity between the splenic marginal zone infiltrates and the gastric lymphoma in the histologically involved cases. Amplifiable DNA could be extracted from only 5 of the remaining 15 cases. In 3 of these cases, including the case previously studied using an anti-idiotype, involvement of the splenic marginal zone could be confirmed using microdissection and clone-specific PCR. No involvement could be detected in the remaining 2 cases. In addition, we have shown that mucosal addressin cell adhesion molecule-1 (MAdCAM-1), the primary homing receptor of gut-mucosa for lymphocytes, was strongly expressed by the sinus lining cells of the splenic marginal zone. These results provide strong evidence for preferential involvement of the marginal zone when gastric MALT lymphomas disseminate to the spleen, which is in keeping with the notion that the marginal zone B cells are the normal counterparts of MALT lymphoma cells.  相似文献   
80.
In a photo, motion blur can be used as an artistic style to convey motion and to direct attention. In panning or tracking shots, a moving object of interest is followed by the camera during a relatively long exposure. The goal is to get a blurred background while keeping the object sharp. Unfortunately, it can be difficult to impossible to precisely follow the object. Often, many attempts or specialized physical setups are needed. This paper presents a novel approach to create such images. For capturing, the user is only required to take a casually recorded hand‐held video that roughly follows the object. Our algorithm then produces a single image which simulates a stabilized long time exposure. This is achieved by first warping all frames such that the object of interest is aligned to a reference frame. Then, optical flow based frame interpolation is used to reduce ghosting artifacts from temporal undersampling. Finally, the frames are averaged to create the result. As our method avoids segmentation and requires little to no user interaction, even challenging sequences can be processed successfully. In addition, artistic control is available in a number of ways. The effect can also be applied to create videos with an exaggerated motion blur. Results are compared with previous methods and ground truth simulations. The effectiveness of our method is demonstrated by applying it to hundreds of datasets. The most interesting results are shown in the paper and in the supplemental material.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号