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   143916篇
  免费   15384篇
  国内免费   8658篇
工业技术   167958篇
  2024年   346篇
  2023年   2136篇
  2022年   4433篇
  2021年   6434篇
  2020年   4786篇
  2019年   3744篇
  2018年   4198篇
  2017年   4716篇
  2016年   4313篇
  2015年   6597篇
  2014年   7980篇
  2013年   9447篇
  2012年   11138篇
  2011年   11719篇
  2010年   10745篇
  2009年   10519篇
  2008年   10126篇
  2007年   9447篇
  2006年   8732篇
  2005年   7440篇
  2004年   4967篇
  2003年   3788篇
  2002年   3534篇
  2001年   3068篇
  2000年   2647篇
  1999年   2382篇
  1998年   1518篇
  1997年   1363篇
  1996年   1209篇
  1995年   1037篇
  1994年   800篇
  1993年   598篇
  1992年   482篇
  1991年   351篇
  1990年   293篇
  1989年   231篇
  1988年   186篇
  1987年   116篇
  1986年   101篇
  1985年   44篇
  1984年   40篇
  1983年   18篇
  1982年   32篇
  1981年   27篇
  1980年   33篇
  1979年   12篇
  1978年   12篇
  1976年   10篇
  1959年   14篇
  1951年   17篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
Qin  Yuancheng  Yao  Yingbiao  Feng  Wei  Li  Pei  Xu  Xin 《Wireless Networks》2022,28(8):3337-3347
Wireless Networks - With the dynamic voltage scaling (DVS) technology, the terminal node (TN) can dynamically adjust its computational speed, thus providing a new way to save energy during task...  相似文献   
4.
Feng  Zilong  Na  Zhenyu  Xiong  Mudi  Ji  Chenglan 《Mobile Networks and Applications》2022,27(4):1578-1592
Mobile Networks and Applications - Due to fast deployment, strong survivability and flexible scheduling, multiple unmanned aerial vehicles (UAV) can synergistically optimize the trajectory and...  相似文献   
5.
6.
Chen  Huiling  Zhang  Chunmei  Xu  Qin  Feng  Yuli 《Neural Processing Letters》2022,54(1):181-205
Neural Processing Letters - This paper is concerned with topology identification of stochastic multi-weighted complex networks based on adaptive synchronization. Different from previous work,...  相似文献   
7.
Corrosion and salt deposition problems severely restrict the industrialization of supercritical water oxidation. Transpiring wall reactor can effectively weaken these two problems by a protective water film. In this work, methanol was selected as organic matter, and the influences of vital structural parameters on water film properties and organic matter removal were studied via numerical simulation. The results indicate that higher than 99% of methanol conversion could be obtained and hardly affected by transpiration water layer, transpiring wall porosity and inner diameter. Increasing layer and porosity reduced reactor center temperature, but inner diameter's influence was lower relatively. Water film temperature reduced but coverage rate raised as layer, porosity, and inner diameter increased. Notably, the whole reactor was in supercritical state and coverage rate was only approximately 85% in the case of one layer. Increasing reactor length affected slightly the volume of the upper supercritical zone but enlarged the subcritical zone.  相似文献   
8.
近年来在下扬子地区页岩气地质调查井所获取的地层岩心资料,揭示该地区下志留统风暴沉积较为发育。基于精细的岩心观察描述,详细分析了下扬子地区下志留统高家边组下段中上部风暴沉积的特征,并阐明了风暴作用对泥页岩的影响。研究表明:研究区风暴岩岩性偏细,以粉砂岩为主,石英含量较高,结构成熟度较低,具2种不同的粒度概率曲线;主要发育底部冲刷面、块状层理、平行层理、丘状交错层理、波纹交错层理、准同生变形构造等沉积构造;垂向上主要识别出4种风暴沉积序列,均具有从底到顶粒度变细的沉积特征,不同的沉积序列与风暴流能量的强弱有关。下扬子地区早志留世频繁的风暴活动与研究区的古地理背景和古气候条件具有内在联系。特大型风暴对浅海陆棚深水区的细粒泥质沉积物特征产生重要影响,包括降低有机质含量、减少单层厚度、破坏垂向连续性、改变原始沉积构造和侧向稳定性等,总体上降低了泥页岩的品质。因此,研究认为在页岩气的勘探和评价过程中应重视风暴因素对陆棚深水区原始泥质沉积物的影响。  相似文献   
9.
10.
Zhang  Jiawei  Li  Chen  Rahaman  Md Mamunur  Yao  Yudong  Ma  Pingli  Zhang  Jinghua  Zhao  Xin  Jiang  Tao  Grzegorzek  Marcin 《Artificial Intelligence Review》2022,55(4):2875-2944

Microorganisms such as bacteria and fungi play essential roles in many application fields, like biotechnique, medical technique and industrial domain. Microorganism counting techniques are crucial in microorganism analysis, helping biologists and related researchers quantitatively analyze the microorganisms and calculate their characteristics, such as biomass concentration and biological activity. However, traditional microorganism manual counting methods, such as plate counting method, hemocytometry and turbidimetry, are time-consuming, subjective and need complex operations, which are difficult to be applied in large-scale applications. In order to improve this situation, image analysis is applied for microorganism counting since the 1980s, which consists of digital image processing, image segmentation, image classification and suchlike. Image analysis-based microorganism counting methods are efficient comparing with traditional plate counting methods. In this article, we have studied the development of microorganism counting methods using digital image analysis. Firstly, the microorganisms are grouped as bacteria and other microorganisms. Then, the related articles are summarized based on image segmentation methods. Each part of the article is reviewed by methodologies. Moreover, commonly used image processing methods for microorganism counting are summarized and analyzed to find common technological points. More than 144 papers are outlined in this article. In conclusion, this paper provides new ideas for the future development trend of microorganism counting, and provides systematic suggestions for implementing integrated microorganism counting systems in the future. Researchers in other fields can refer to the techniques analyzed in this paper.

  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