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   150872篇
  免费   24965篇
  国内免费   6435篇
电工技术   9338篇
技术理论   4篇
综合类   8451篇
化学工业   34077篇
金属工艺   7660篇
机械仪表   8809篇
建筑科学   9972篇
矿业工程   3450篇
能源动力   4444篇
轻工业   14323篇
水利工程   2787篇
石油天然气   5844篇
武器工业   1345篇
无线电   19945篇
一般工业技术   23731篇
冶金工业   6127篇
原子能技术   1435篇
自动化技术   20530篇
  2024年   418篇
  2023年   1649篇
  2022年   3311篇
  2021年   5027篇
  2020年   4778篇
  2019年   5791篇
  2018年   6083篇
  2017年   6750篇
  2016年   7000篇
  2015年   8386篇
  2014年   9629篇
  2013年   11812篇
  2012年   11028篇
  2011年   11364篇
  2010年   10645篇
  2009年   10226篇
  2008年   9714篇
  2007年   8996篇
  2006年   8443篇
  2005年   6933篇
  2004年   5549篇
  2003年   5191篇
  2002年   5194篇
  2001年   4570篇
  2000年   3509篇
  1999年   2531篇
  1998年   1452篇
  1997年   1276篇
  1996年   1078篇
  1995年   864篇
  1994年   671篇
  1993年   455篇
  1992年   361篇
  1991年   312篇
  1990年   273篇
  1989年   230篇
  1988年   147篇
  1987年   131篇
  1986年   87篇
  1985年   66篇
  1984年   49篇
  1983年   53篇
  1982年   40篇
  1981年   33篇
  1980年   34篇
  1979年   22篇
  1978年   18篇
  1976年   18篇
  1975年   13篇
  1973年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Zhao  Jiandong  Lei  Wei  Li  Zijian  Zhao  Dongfeng  Han  Mingmin  Hou  Xiaoqing 《Multimedia Tools and Applications》2022,81(4):4753-4780
Multimedia Tools and Applications - The crowding in bus is an important factor affecting passenger satisfaction and bus dispatching level. However, how to use video images to detect crowding...  相似文献   
2.
3.
This study investigated the inhibitory effects of curcumin and piperine on fluorescent advanced glycation end products (fAGEs) formation in a bovine serum albumin (BSA)–fructose model. Model systems of BSA and fructose were prepared, and curcumin or piperine was added. fAGEs and BSA oxidation product (dityrosine, kynurenine and N'-formylkynurenine) contents were determined. The results showed that fAGEs content decreased with increasing concentration of curcumin and piperine (P < 0.05). Addition of curcumin and piperine at 160 µg mL−1 could inhibit fluorescent AGEs by 100% and 93% respectively. Dityrosine and N'-formylkynurenine contents decreased as curcumin and piperine concentration increased (P < 0.05). Furthermore, the result of principal component analysis indicated that curcumin and piperine markedly impeded BSA oxidation, resulting in a lower level of fAGEs in model systems. Therefore, adding curcumin and piperine may facilitate reduced fAGEs levels in BSA–fructose model.  相似文献   
4.
5.
6.
7.
Pathogens pose a serious challenge to environmental sanitation and a threat to public health.The frequent use of chemicals for sterilization in recent years has not only caused secondary damage to the environment but also increased pathogen resistance to drugs,which further threatens public health.To address this issue,the use of non-chemical antibacterial means has become a new trend for environmental disinfection.In this study,we developed red phosphorus nanoparticles(RPNPs),a safe and degradable photosensitive material with good photocatalytic and photothermal properties.The red phosphorus nanoparticles were prepared using a template method and ultrasonication.Under the irradiation of simulated sunlight for 20 min,the RPNPs exhibited an efficiency of 99.98%in killing Staphylococcus aureus due to their excellent photocatalytic and photothermal abilities.Transmission electron microscopy and ultraviolet–visible spectroscopy revealed that the RPNPs exhibited degradability within eight weeks.Both the RPNPs and their degradation products were nontoxic to fibroblast cells.Therefore,such RPNPs are expected to be used as a new type of low-cost,efficient,degradable,biocompatible,and eco-friendly photosensitive material for environmental disinfection.  相似文献   
8.
黄科  袁启平  董薇  孙沂昆  亢勇  王天翔 《电视技术》2021,45(10):129-135
恶意代码数量已经呈现爆炸式增长,对于恶意代码的检测防护显得尤为重要.近几年,基于深度学习的恶意代码检测方法开始出现,基于此,提出一种新的检测方法,将恶意代码二进制文件转化为十进制数组,并利用一维卷积神经网络(1 Dimention Convolutional Neural Networks,1D CNN)对数组进行分类和识别.针对代码家族之间数量不平衡的现象,该算法选择在分类预测上表现良好的XGBoost,并对Vision Research Lab中的25个不同恶意软件家族的9458个恶意软件样本进行了实验.实验结果表明,所提的方法分类预测精度达到了97%.  相似文献   
9.
10.
Given the continuing issues of environment and energy, methane dry reforming for syngas production have sparked interest among researchers, but struggled with the process immaturity owing to catalyst deactivation. This review summarizes the recent advances in the development of efficient and stable catalysts with strong resistance to coking and metal sintering, including the application of novel materials, the assessment of advanced characterizations and the compatibility to improved reaction system. One feasible option is the crystalline oxide catalysts (perovskite, pyrochlore, spinel and LDHs), which feature a fine metal dispersion and surface confinement effect via a metal exsolution strategy and exhibit superior reactivity and stability. Some new materials (h-BN, clays and MOFs) also extend the option because of their unique morphology and microstructure. It also is elaborated that progresses were achieved in advanced characterizations application, leading to success in the establishment of reaction mechanisms and attributions to the formed robust catalysts. In addition, the perspective described the upgrade of reaction system to a higher reaction efficiency and milder reaction conditions. The combination of efficient reaction systems and robust catalysts paves a way for a scaling-up application of the process.  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