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   87884篇
  免费   6918篇
  国内免费   3344篇
电工技术   4842篇
技术理论   5篇
综合类   5668篇
化学工业   15222篇
金属工艺   5360篇
机械仪表   5467篇
建筑科学   7749篇
矿业工程   2535篇
能源动力   2367篇
轻工业   5345篇
水利工程   1543篇
石油天然气   5163篇
武器工业   683篇
无线电   9229篇
一般工业技术   10471篇
冶金工业   4361篇
原子能技术   1061篇
自动化技术   11075篇
  2024年   131篇
  2023年   1404篇
  2022年   1975篇
  2021年   3152篇
  2020年   2560篇
  2019年   2129篇
  2018年   2496篇
  2017年   2832篇
  2016年   2416篇
  2015年   3242篇
  2014年   4103篇
  2013年   5037篇
  2012年   5547篇
  2011年   5933篇
  2010年   5034篇
  2009年   4970篇
  2008年   4801篇
  2007年   4578篇
  2006年   4882篇
  2005年   4337篇
  2004年   2895篇
  2003年   2491篇
  2002年   2278篇
  2001年   2011篇
  2000年   2266篇
  1999年   2660篇
  1998年   2158篇
  1997年   1754篇
  1996年   1802篇
  1995年   1468篇
  1994年   1197篇
  1993年   847篇
  1992年   689篇
  1991年   547篇
  1990年   389篇
  1989年   328篇
  1988年   263篇
  1987年   176篇
  1986年   107篇
  1985年   79篇
  1984年   51篇
  1983年   29篇
  1982年   40篇
  1981年   28篇
  1980年   22篇
  1979年   6篇
  1978年   2篇
  1965年   2篇
  1956年   1篇
  1932年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Zhang  Guangsheng  Liu  Bo  Zhu  Tianqing  Zhou  Andi  Zhou  Wanlei 《Artificial Intelligence Review》2022,55(6):4347-4401

The concerns on visual privacy have been increasingly raised along with the dramatic growth in image and video capture and sharing. Meanwhile, with the recent breakthrough in deep learning technologies, visual data can now be easily gathered and processed to infer sensitive information. Therefore, visual privacy in the context of deep learning is now an important and challenging topic. However, there has been no systematic study on this topic to date. In this survey, we discuss algorithms of visual privacy attacks and the corresponding defense mechanisms in deep learning. We analyze the privacy issues in both visual data and visual deep learning systems. We show that deep learning can be used as a powerful privacy attack tool as well as preservation techniques with great potential. We also point out the possible direction and suggestions for future work. By thoroughly investigating the relationship of visual privacy and deep learning, this article sheds insights on incorporating privacy requirements in the deep learning era.

  相似文献   
42.
43.
44.
Ceramic microparticles have great potentials in various fields such as materials engineering, biotechnology, microelectromechanical systems, etc. Morphology of the microparticle performs an important role on their application. To date, it remains difficult to find an effective and controllable way for fabricating nonspherical ceramic microparticles with 3D features. This work demonstrates a method that combines UV light lithography and single emulsion opaque-droplet-templated microfluidic molding to prepare the crescent-shaped ceramic microparticles. By tailoring the intensity of UV light and flow rate of fluid, the shapes of microparticles are accordingly tuned. Therefore, varieties of crescent-shaped microparticles and their variations have been fabricated. After sintering, the crescent-shaped alumina ceramic microparticles were obtained. Benefitting from the light absorption and scattering behavior of most ceramic nanoparticles, this system can serve as a general platform to produce crescent-shaped microparticles made from different materials, and hold great potentials for applications in microrobotics, structural materials in MEMS, and biotechnology.  相似文献   
45.
The deposition of amyloid-beta (Aβ) through the cleavage of amyloid-beta precursor protein (APP) is a biomarker of Alzheimer’s disease (AD). This study used QIAGEN Ingenuity Pathway Analysis (IPA) to conduct meta-analysis on the molecular mechanisms by which methamphetamine (METH) impacts AD through modulating the expression of APP. All the molecules affected by METH and APP were collected from the QIAGEN Knowledge Base (QKB); 78 overlapping molecules were identified. Upon simulation of METH exposure using the “Molecule Activity Predictor” feature, eight molecules were found to be affected by METH and exhibited activation relationships on APP expression at a confidence of p = 0.000453 (Z-score = 3.51, two-tailed). Core Analysis of these eight molecules identified High Mobility Group Box protein 1 (HMGB1) signaling pathway among the top 5 canonical pathways with most overlap with the 8-molecule dataset. Simulated METH exposure increased APP expression through HMGB1 at a confidence of p < 0.00001 (Z-score = 7.64, two-tailed). HMGB1 is a pathogenic hallmark in AD progression. It not only increases the production of inflammatory mediators, but also mediates the disruption of the blood-brain barrier. Our analyses suggest the involvement of HMGB1 signaling pathway in METH-induced modulation of APP as a potential casual factor of AD.  相似文献   
46.
Hu  Huikang  Kong  Weiguo  Jin  Weimin  Liu  Chunxia  Zhou  Shijian 《Catalysis Letters》2021,151(6):1556-1565
Catalysis Letters - For the noble-metal based catalysts, the metal dispersion and sinter resistance of the metal nanoparticles (NPs) are the most vital factors for their application in series...  相似文献   
47.
Flexible scintillating fiber plays an important role in X-ray radiation monitoring and high-resolution medical imaging, while construction of scintillating fiber derived from the commercial material system meet with limited success. Here, we report the design and successful fabrication of the Ce-activated lutetium aluminum silicate glass, nanostructured glass, and fiber, and explore their scintillating properties. The scintillating glass with optimized composition and optical properties is determined. The crystallization behavior of lutetium aluminum silicate glass is studied and the nanostructured glass embedded with orthorhombic Lu2Si2O7 phase is successfully constructed for the first time. Importantly, the crystalline layer thickness of the nanostructured glass can be finely tuned and ~172.89% enhancement in the scintillating performance can be achieved. Furthermore, the fiber with large sized core is fabricated and its radiation response properties are tested. The results show that it exhibits high sensitivity and its scintillating emission is lineally dependent on the X-ray power, indicating the potential application for radiation detection.  相似文献   
48.
A digital light processing (DLP) technology has been developed for 3D printing lead-free barium titanate (BTO) piezoelectric ceramics. By comparing the curing and rheological properties of slurries with different photosensitive monomer, a high refractive index monomer acryloyl morpholine (ACMO) was chosen, and a design and preparation method of BTO slurry with high solid content, low viscosity and high curing ability was proposed. By further selecting the printing parameters, the single-layer exposure time was reduced and the forming efficiency has been greatly improved. Sintered specimens were obtained after a nitrogen-air double-step debinding and furnace sintering process, and the BTO ceramics fabricated with 80 wt% slurry shows the highest relative density (95.32 %) and piezoelectric constant (168.1 pC/N). Furthermore, complex-structured BTO ceramics were prepared, impregnated by epoxy resin and finally assembly made into hydrophones, which has significance for the future design and manufacture of piezoelectric ceramic-based composites that used in functional devices.  相似文献   
49.
Charge-based field-effect transistors (FETs) greatly suffer from unavoidable carrier scattering and heat dissipation. Analogous to valley degree of freedom in semiconductors, chiral anomaly current in Weyl/Dirac semimetals is theoretically predicted to be nearly nondissipative over long distances, but still lacks experimental ways to efficiently control its transport. Here, field-effect chirality devices are demonstrated with Dirac semimetal PtSe2, in which its Fermi level is close to the Dirac point in the conduction band owing to intrinsic defects. The chiral anomaly is further corroborated by the planar Hall effect and nonlocal valley transport measurement, which can also be effectively modulated by external fields, showing robust nonlocal valley transport with micrometer diffusion length. Similar to charge-based FETs, the chiral conductivity in PtSe2 devices can be modulated by electrostatic gating with an ON/OFF ratio of more than 103. Basic logic functions in the devices are also demonstrated with electric and magnetic fields as input signals.  相似文献   
50.
移动边缘云是公司“云+5G”双引擎战略的最佳契合点,边缘网络是发挥移动云“大云”产品和5G网络融合优势,实现云网统筹、构建运营商“连接+计算”核心能力的关键。运营商传统接入网存在云网割裂、分段入云和组网复杂等突出问题,难以适应边缘业务敏捷交付要求。本文通过深入分析边缘云业务特征和技术架构,对标业界主流云商建设实践,研究基于云网PoP网的边缘网络建设思路,创新性提出云网一体化规划设计和建设交付流程变革,基于云网POP统一网络和业务锚点,构建Overlay和Underlay融合双层加速网络架构,探索Spine-leaf化的新型城域接入网实现L3下沉和弹性扩容等方法,实现“云+网+应用”一体化敏捷交付的边缘网络能力。  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