首页 | 官方网站   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   7791篇
  免费   393篇
  国内免费   24篇
工业技术   8208篇
  2023年   69篇
  2022年   41篇
  2021年   155篇
  2020年   153篇
  2019年   139篇
  2018年   192篇
  2017年   186篇
  2016年   217篇
  2015年   163篇
  2014年   270篇
  2013年   362篇
  2012年   444篇
  2011年   510篇
  2010年   360篇
  2009年   410篇
  2008年   370篇
  2007年   305篇
  2006年   230篇
  2005年   223篇
  2004年   187篇
  2003年   166篇
  2002年   166篇
  2001年   120篇
  2000年   108篇
  1999年   150篇
  1998年   785篇
  1997年   409篇
  1996年   302篇
  1995年   183篇
  1994年   143篇
  1993年   163篇
  1992年   38篇
  1991年   40篇
  1990年   48篇
  1989年   54篇
  1988年   51篇
  1987年   41篇
  1986年   26篇
  1985年   22篇
  1984年   4篇
  1983年   10篇
  1982年   11篇
  1981年   17篇
  1980年   14篇
  1979年   3篇
  1978年   2篇
  1977年   29篇
  1976年   109篇
  1975年   2篇
  1955年   1篇
排序方式: 共有8208条查询结果,搜索用时 15 毫秒
61.
Cloud service providers offer virtual resources to users, who then pay for as much as they use. High‐speed networks help to overcome the limitation of geographical distances between clients and cloud servers, which encourage users to adopt cloud storage services for data backup and sharing. However, users use only a few cloud storage services because of the complexity of managing multiple accounts and distributing data to store. In this paper, we propose the client‐defined management architecture (CLIMA) that redefines a storage service by coordinating multiple cloud storage services from clients. We address practical issues of coordinating multiple cloud service providers using a client‐based approach. We implement a prototype as a realization of CLIMA, which achieves both reliability and privacy protection using erasure code and higher performance by optimally scheduling data transmission. We use our prototype to evaluate the benefits of CLIMA on commercial cloud storage service providers. Finally, CLIMA empowers clients to increase the manageability and flexibility of cloud storage services. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
62.
Li[Ni0.65Co0.13Mn0.22]O2 cathode with two‐sloped full concentration gradient (TSFCG), maximizing the Ni content in the inner part of the particle and the Mn content near the particle surface, is synthesized via a specially designed batch‐type reactor. The cathode delivers a discharge capacity of 200 mAh g?1 (4.3 V cutoff) with excellent capacity retention of 88% after 1500 cycles in a full‐cell configuration. Overall electrochemical performance of the TSFCG cathode is benchmarked against conventional cathode (CC) with same composition and commercially available Li[Ni0.8Co0.15Al0.05]O2 (NCA). The TSFCG cathode exhibits the best cycling stability, rate capability, and thermal stability of the three electrodes. Transmission electron microscopy analysis of the cycled TSFCG, CC, and NCA cathodes shows that the TSFCG electrode maintains both its mechanical and structural integrity whereas the NCA electrode nearly pulverizes due to the strain during cycling.  相似文献   
63.
64.
65.
66.
67.
ABSTRACT

In order to develop a methodology to guarantee the conformance to operational discharge limits for liquid effluent from a NPP at an early stage of design, a risk-informed approach was proposed and its applicability was verified for APR 1400. Existing methodology to calculate risk-based detection limit for a single radionuclide was improved by incorporating a new model to derive more realistic pathway dose factors. A new simple expression was also proposed to adjust risk-based detection limits for multiple radionuclides mixture if necessary. In addition, a new procedure to warrant the compliance with discharge limits by controlling detection limits of only a few principal radionuclides was established in accordance with risk-informed concept. Through case studies for APR 1400 to be commissioned at a hypothetical site, it was shown that calculated pathway dose factors are more realistic for majority of radionuclides. It also turns out that neither present detection limits nor unadjusted risk-based detection limits can be justified when the radionuclide composition is unknown, however further adjustment of detection limits or increasing additional dilution factor resolves the problem. Finally, ten principal radionuclides were identified and shown to be enough for liquid effluent control at APR 1400 from a risk-informed point of view.  相似文献   
68.
Mun  Changbae  Yoon  Sejun  Park  Hyunseok 《Scientometrics》2019,121(2):633-652
Scientometrics - This paper proposes a new method for decomposing a technological domain (TD). Specifically, the method identifies sub-TDs at the different levels of technological hierarchy within...  相似文献   
69.
70.
The development of smart inks that change color and transparency in response to external stimuli is very important for various fields, from modern art to safety and anticounterfeiting technology. A uniaxially oriented diacetylene thin film on a macroscopic area is obtained by coating, self-assembling and topochemical photopolymerizing of imidazolium-functionalized diacetylenes (M-DA and T-DA) and 4,6-decadiyne ink (70 wt%:20 wt%:10 wt%) exhibiting a lyotropic smectic A liquid-crystalline phase at room temperature. The color and transparency of letters and symbols written with the DA-based secret inks change reversibly from blue to red as well as from colorless transparent to black opaque depending on the temperature and polarization axis. A secret code written with thermoresponsive and polarization-dependent secret inks consisting of imidazolium-functionalized diacetylenes is successfully deciphered by wearing polaroid glasses and holding a burning torch.  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-23

京公网安备 11010802026262号