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   4844篇
  免费   272篇
  国内免费   220篇
电工技术   687篇
技术理论   1篇
综合类   129篇
化学工业   100篇
金属工艺   63篇
机械仪表   205篇
建筑科学   244篇
矿业工程   18篇
能源动力   269篇
轻工业   33篇
水利工程   27篇
石油天然气   26篇
武器工业   16篇
无线电   705篇
一般工业技术   330篇
冶金工业   39篇
原子能技术   21篇
自动化技术   2423篇
  2024年   8篇
  2023年   95篇
  2022年   121篇
  2021年   173篇
  2020年   193篇
  2019年   99篇
  2018年   74篇
  2017年   143篇
  2016年   161篇
  2015年   197篇
  2014年   350篇
  2013年   238篇
  2012年   284篇
  2011年   371篇
  2010年   286篇
  2009年   278篇
  2008年   346篇
  2007年   371篇
  2006年   427篇
  2005年   342篇
  2004年   241篇
  2003年   152篇
  2002年   91篇
  2001年   58篇
  2000年   64篇
  1999年   35篇
  1998年   33篇
  1997年   26篇
  1996年   21篇
  1995年   11篇
  1994年   15篇
  1993年   5篇
  1992年   7篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   4篇
  1987年   1篇
  1986年   2篇
  1983年   2篇
  1979年   1篇
排序方式: 共有5336条查询结果,搜索用时 20 毫秒
1.
Powering wearable bioelectronics with decent skin conformability and wearing comfort is highly desired. Fiber batteries could provide an attractive alternative to traditional rigid ones and present a compelling solution to this problem. In this review, we will discuss the various classes of fiber batteries, including lithium batteries, zinc batteries, and other types of fiber batteries. We will then report the latest research progress on each battery category through its working mechanism, materials usage, structure design, and wearable applications. Finally, we provide insights into current challenges and future applications of fiber batteries, aiming to promote the development of low-cost and high-performance fiber battery technologies for wearable bioelectronics.  相似文献   
2.
Diagnosing the cardiovascular disease is one of the biggest medical difficulties in recent years. Coronary cardiovascular (CHD) is a kind of heart and blood vascular disease. Predicting this sort of cardiac illness leads to more precise decisions for cardiac disorders. Implementing Grid Search Optimization (GSO) machine training models is therefore a useful way to forecast the sickness as soon as possible. The state-of-the-art work is the tuning of the hyperparameter together with the selection of the feature by utilizing the model search to minimize the false-negative rate. Three models with a cross-validation approach do the required task. Feature Selection based on the use of statistical and correlation matrices for multivariate analysis. For Random Search and Grid Search models, extensive comparison findings are produced utilizing retrieval, F1 score, and precision measurements. The models are evaluated using the metrics and kappa statistics that illustrate the three models’ comparability. The study effort focuses on optimizing function selection, tweaking hyperparameters to improve model accuracy and the prediction of heart disease by examining Framingham datasets using random forestry classification. Tuning the hyperparameter in the model of grid search thus decreases the erroneous rate achieves global optimization.  相似文献   
3.
Electrical energy is one of the key components for the development and sustainability of any nation. India is a developing country and blessed with a huge amount of renewable energy resources still there are various remote areas where the grid supply is rarely available. As electrical energy is the basic requirement, therefore it must be taken up on priority to exploit the available renewable energy resources integrated with storage devices like fuel cells and batteries for power generation and help the planners in providing the energy-efficient and alternative solution. This solution will not only meet electricity demand but also helps reduce greenhouse gas emissions as a result the efficient, sustainable and eco-friendly solution can be achieved which would contribute a lot to the smart grid environment. In this paper, a modified grey wolf optimizer approach is utilized to develop a hybrid microgrid based on available renewable energy resources considering modern power grid interactions. The proposed approach would be able to provide a robust and efficient microgrid that utilizes solar photovoltaic technology and wind energy conversion system. This approach integrates renewable resources with the meta-heuristic optimization algorithm for optimal dispatch of energy in grid-connected hybrid microgrid system. The proposed approach is mainly aimed to provide the optimal sizing of renewable energy-based microgrids based on the load profile according to time of use. To validate the proposed approach, a comparative study is also conducted through a case study and shows a significant savings of 30.88% and 49.99% of the rolling cost in comparison with fuzzy logic and mixed integer linear programming-based energy management system respectively.  相似文献   
4.
Smart home automation provides residents with relief and convenience in everyday life and allows for self-determined aging in place. Yet, market penetration is offset by user concerns related to privacy and trust issues: With increasing system complexity, users may perceive a loss of control and fear technical unreliability. While barriers to acceptance in terms of privacy and trust are well understood when considered separately, they are hardly investigated in conjunction so far. We conducted a quantitative study using Adaptive Choice-Based Conjoint Analysis via an online questionnaire. We explored how aspects of privacy and trust determine the willingness to use smart homes from the perspective of (future) users (n = 137, 18 to 64 years of age), and also with respect to the level of automation and application field. Results show that semi-automated systems are rather preferred than fully automated smart home technology. The perceived reliability of automation is the most important acceptance determinant, followed by the location of data storage. Whereas the awareness to use (e.g., recommendations), the type of data, and application field are less important factors for the overall willingness to use smart homes. Findings inform scientists in the field of human-automation interaction and technical developers of smart home automation for technology innovation adapted to user needs.  相似文献   
5.
In order to maximise European, national and regional research and innovation potential the European Union is investing in these fields through different funding mechanisms such as the ESIF or H2020 programme. This investment plan is part of the European 2020 strategy, where the concept of Smart Specialisation is also included.Smart Specialisation is an innovation policy concept designed to promote the efficient and effective use of public investment in regional innovation in order to achieve economic growth. The Smart Specialisation Platform was created to support this concept by assisting regions and Member States in developing, implementing and reviewing their research and innovation Smart Specialisation strategies.The Smart Specialisation Platform comprises several thematic platforms. The thematic Smart Specialisation Platform on energy (S3PEnergy) is a joint initiative of three European Commission services: DG REGIO, DG ENER, and the Joint Research Centre (JRC). The main objective of the S3PEnergy is to support the optimal and effective uptake of the Cohesion Policy funds for energy, and to better align energy innovation activities at national, local and regional level through the identification of the technologies and innovative solutions that support in the most cost-effective way the EU energy policy priorities.In the particular case of hydrogen technologies, the activities of the platform are mainly focused on supporting the new Fuel Cells and Hydrogen Joint Undertaking (FCH JU) initiative involving regions and cities. To date, more than 80 European cities and regions have committed to participate in this initiative through the signature of a Memorandum of Understanding, and more participants are expected to join. S3PEnergy is helping in the identification of potential combination of H2020 funding (provided through FCH JU) and ESIF.To identify potential synergies among these two funding sources, a mapping of the different ESIF opportunities has been performed. In order to map these opportunities, Operational Programmes (OPs) and research and innovation strategies for Smart Specialisation (RIS3) of the different European regions and Member States were analysed. The results of this mapping and analysis are presented in this paper.  相似文献   
6.
Smart cities are built upon information and communication technologies (ICTs) to enable a broad range of advanced services. Through a comprehensive literature review, this study identified four pitfalls brought by the pervasive application of ICT, including information insecurity, privacy leakage, information islands, and digital divide. Therefore, a questionnaire survey together with 27 interviews was conducted in Hong Kong to investigate how the public perceived these pitfalls within the context of mobile apps providing real-time parking information which form a major part of smart mobility. System insecurity and privacy leakage were found to arouse worries among the app-users while their awareness of protecting personal data was found to have room for improvement. Islands of real-time parking information occur as a result of the lack of collaboration among private carpark operators. Digital divide existed widely among the disadvantaged groups and the problem cannot be solved by mere provision of ICT facilities. Overall, technologies alone cannot make a city smart or smarter. It is the suitable way in which ICTs are used to serve all citizens that matters.  相似文献   
7.
The ‘actually existing’ smart city is not a monolith. It is not directed by a universal logic, nor does it develop in a standardised way. As recent research has argued, the spatial, material, and political contexts of cities have major influence over what smart urbanism looks like in practice. This paper adds analytical depth to, and broadens the geographical scope of, research on the variegated modes of making smart cities. Based on empirical research in multiple Australian cities we use three case studies to explore three different modes of smart urbanism, each one centred on the interests of a different key actor: corporate-centric, citizen-centric, and planner-centric. These different modes can, and do, co-exist in the same city. At times, they are competing logics that fight to pull the city in different directions. Yet, they can also work together to shape smart city initiatives. In describing these different modes, we pay particular attention to the ways that these projects and strategies must contend with the already existing spatial, cultural, and political contexts of each place.  相似文献   
8.
Lack of constraint-free crane path planning is one of the critical concerns in the dynamic on-site assembly process of prefabrication housing production (PHP). For decades, researchers and practitioners have endeavored to improve both the efficiency and safety of crane path planning from either static environment or re-planning the path when colliding with constraints or periodically updating the path in the dynamic environment. However, there is a lack of approach related to the in-depth exploration of the nature of dynamic constraints so as to assist the crane operators in making adaptive path re-planning decisions by categorizing and prioritizing constraints. To address this issue, this study develops the smart work packaging (SWP)-enabled constraints optimization service. This service embraces the core characteristics of SWP, including adaptivity, sociability, and autonomy to achieve autonomous initial path planning, networked constraints classification, and adaptive decisions on path re-planning. This service is simulated and verified in the BIM environment, and it is found that SWP-enabled constraints optimization service can generate the constraint-free path when it is necessary.  相似文献   
9.
“Smart firefighting” construction as a part of the “smart city” has been a concern of the public security and fire agencies at all levels. In this study, the status, problems, and reflections of “smart firefighting” construction in China are discussed. A recent survey indicates that China has launched its smart firefighting construction and initially created a new perspective on its regional smart firefighting work based on three main aspects: intelligent disaster perception by Internet of Things (IoT) construction, intelligent disaster prevention by big data construction, and intelligent disaster disposal by emergency rescue platform construction. However, the current smart firefighting construction in China still has some prominent problems such as the data interconnectivity and normalized management of various platforms, the extensibility of smart firefighting platforms, and the intelligent level of smart firefighting researches, which need to be solved urgently. Therefore, we argue that smart firefighting construction in China should establish data interconnectivity, industrial normalized management, 2D/3D geographic information interaction and extension, high-integration fire protection theory, and many other aspects in the near future and truly realize firefighting visualization and efficient data applications for 4D time space. This study could provide valuable reference for smart firefighting and smart city construction.  相似文献   
10.
Silk is a natural fibre obtained from the Bombyx mori silkworm cocoons that can be used in a wide range of fields thanks to its inherent multifunctionality.Post-production steps are necessary to impart colour to the fibres to employ the material for optics and photonic applications, such as in fluorescence-based optofluidic devices in lab-on-a-chip realization.Here we present an intrinsically greener dyeing approach for fabricating naturally functionalized silk, where highly-fluorescent organic dyes with lasing properties are in vivo up-taken by silkworms once introduced in the artificial diet. A detailed photoluminescence spectroscopy investigation is implemented to test whether the dyes are effectively incorporated within the silk proteins, in correlation with the silkworm gland positions where proteins extraction is held. Light amplification characteristics are demonstrated in silk extracted from glands of silkworm fed with artificial diet doped with Rhodamine B dye.  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