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   4372篇
  免费   729篇
  国内免费   451篇
电工技术   482篇
技术理论   1篇
综合类   476篇
化学工业   40篇
金属工艺   44篇
机械仪表   230篇
建筑科学   242篇
矿业工程   70篇
能源动力   60篇
轻工业   28篇
水利工程   103篇
石油天然气   34篇
武器工业   15篇
无线电   929篇
一般工业技术   292篇
冶金工业   81篇
原子能技术   12篇
自动化技术   2413篇
  2024年   10篇
  2023年   60篇
  2022年   158篇
  2021年   178篇
  2020年   208篇
  2019年   131篇
  2018年   130篇
  2017年   146篇
  2016年   220篇
  2015年   227篇
  2014年   356篇
  2013年   315篇
  2012年   361篇
  2011年   450篇
  2010年   334篇
  2009年   307篇
  2008年   325篇
  2007年   359篇
  2006年   296篇
  2005年   213篇
  2004年   185篇
  2003年   140篇
  2002年   114篇
  2001年   78篇
  2000年   57篇
  1999年   45篇
  1998年   29篇
  1997年   23篇
  1996年   18篇
  1995年   6篇
  1994年   13篇
  1993年   11篇
  1992年   2篇
  1991年   8篇
  1990年   3篇
  1989年   4篇
  1988年   3篇
  1986年   3篇
  1985年   5篇
  1982年   1篇
  1981年   3篇
  1979年   2篇
  1978年   3篇
  1977年   1篇
  1976年   7篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1959年   1篇
排序方式: 共有5552条查询结果,搜索用时 20 毫秒
1.
2.
随着社会的发展,信息和文化资源大多来自于图书和网络,而高校图书馆有着丰富的藏书和网络资源,因此,高校图书馆网络资源的共建共享就是科学文化发展的必然结果。那么如何实现网络资源的共建共享,网络资源的共建共享又存在哪些问题,又该如何解决,本文在这里就简单的浅谈一下高校图书馆的资源共享。  相似文献   
3.
We consider ex post demand information sharing in a two-echelon supply chain in which two suppliers sell differentiated products through a common retailer. We model three scenarios of information sharing to characterise the conditions under which information sharing may benefit or hurt different players: (1) no supplier is informed; (2) only one supplier is informed; and (3) both suppliers are informed. We find that the retailer may voluntarily share the low demand information when the product differentiation and demand magnitude satisfy certain conditions. In contrast, the retailer has no incentive to share the high demand information, even though this information benefits the suppliers. To achieve information sharing, we propose a side payment mechanism, which allows benefitted players to subsidise hurtful players. Finally, we extend our model by considering a situation where the suppliers have limited capacity and may invest to ramp up production capacity to satisfy a high demand.  相似文献   
4.
Basins with various mineral resources coexisting and enriching often occupy an important strategic position. The exploration of various mineral resources is repetitive at present due to unshared data and imperfect management mechanism. This situation greatly increases the cost of energy exploitation in the country. Traditional data-sharing mode has several disadvantages, such as high cost, difficulty in confirming the right of data, and lack of incentive mechanism, which make achieving real data sharing difficult. In this paper, we propose a data-sharing mechanism based on blockchain and provide implementation suggestions and technical key points. Compared with traditional data-sharing methods, the proposed data-sharing mechanism can realize data sharing, ensure data quality, and protect intellectual property. Moreover, key points in the construction are stated in the case study section to verify the feasibility of the data-sharing system based on blockchain proposed in this paper.  相似文献   
5.
6.
Herein, we report integrated photo-rechargeable supercapacitors (IPSs) composed of the inverted organic solar cell (iOSC) and solid-state supercapacitor (SC), enabling a high-performance self-power pack. The iOSC serves as a self-power source while the SC functions as energy storage, and both share an indium-tin-oxide (ITO) electrode that affords improved charge propagation across the devices. Combining the energy harvesting and storage devices in this way significantly alleviates the limitations of each device. The power fluctuation of the iOSC can be reimbursed by the SC, thus allowing for a stable energy output. Moreover, the SC is frequently charged by the iOSC during the daytime, thereby greatly reducing the charging time and avoiding a complete discharge as well. When the SC of the IPS is charged by the iOSC under AM 1.5 G of illumination, the overall energy conversion-storage efficiency is ca. 2.27%. Our work provides an effective strategy for further study to fabricate a small, lightweight, portable/wearable self-power pack by integrating energy harvesting and energy storage devices into a single structure.  相似文献   
7.
Fake news dissemination on COVID-19 has increased in recent months, and the factors that lead to the sharing of this misinformation is less well studied. Therefore, this paper describes the result of a Nigerian sample (n = 385) regarding the proliferation of fake news on COVID-19. The fake news phenomenon was studied using the Uses and Gratification framework, which was extended by an “altruism” motivation. The data were analysed with Partial Least Squares (PLS) to determine the effects of six variables on the outcome of fake news sharing. Our results showed that altruism was the most significant factor that predicted fake news sharing of COVID-19. We also found that social media users’ motivations for information sharing, socialisation, information seeking and pass time predicted the sharing of false information about COVID-19. In contrast, no significant association was found for entertainment motivation. We concluded with some theoretical and practical implications.  相似文献   
8.
López-Alt et al.(STOC12)put forward a primitive called multi-key fully homomorphic encryption(MKFHE),in which each involved party encrypts their own data using keys that are independently and randomly chosen whereby arbitrary computations can be performed on these encrypted data by a final collector.Subsequently,several superior schemes based on the standard assumption(LWE)were proposed.Most of these schemes were constructed by expanding a fresh GSW-ciphertext or BGV-ciphertext under a single key to a new same-type ciphertext of the same message under a combination of associated parties’keys.Therefore,the new ciphertext’s size grew more or less linearly with an increase in the number of parties.In this paper,we proposed a novel and simple scheme of MKFHE based on LWE without increasing the size of the ciphertext in the two non-collusion server model.In other words,each party first independently shares their own data between two servers and each server only needs a one-round communication with another to construct a ciphertext of the same plaintext under a sum of associated parties’keys.Our new ciphertext under multiple keys has the same size as that of the original one with only one-round communication between two servers.The communication complexity is O(kmlogq)-bit,where k is the number of input ciphertexts involved,m is the size of a GSW-ciphertext and q is a modulus.In conclusion,we proved that our scheme is CPA-secure against semi-honest adversaries.  相似文献   
9.
基于事故后果的安全规划法常运用于重大危险源的土地使用规划,MAPGIS具有空间地理信息方面的功能优势。安全规划的图形可以在MAPGIS环境下进行数据的提取、转换、共享、属性调整和危险分区,实现基于后果的安全规划法与MAPGIS技术的结合。以某规划的石化项目发生池火灾为实证分析,结合有关计算模型,模拟得到了MAPGIS环境下有关池火灾的危险分区图。  相似文献   
10.
The shared housing sector is a growing private rental submarket. Researchers have sought to analyse the drivers of this growth, the benefits of shared housing for tenants, landlords and wider urban systems, as well as risks for tenants and local planning systems. Yet, there is limited research exploring the diversity of the shared housing sector. In particular, analysis of room or space sharing with non-related adults is lacking. This paper explores the characteristics, geography and impact of room sharing across Sydney. By analysing online accommodation listings this paper provides insights for policymakers seeking to monitor and regulate shared room accommodation.  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