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   1972871篇
  免费   68503篇
  国内免费   29580篇
电工技术   65267篇
技术理论   60篇
综合类   42396篇
化学工业   349736篇
金属工艺   91395篇
机械仪表   73615篇
建筑科学   86118篇
矿业工程   28130篇
能源动力   63343篇
轻工业   143031篇
水利工程   24781篇
石油天然气   68125篇
武器工业   4295篇
无线电   248649篇
一般工业技术   331008篇
冶金工业   178579篇
原子能技术   38963篇
自动化技术   233463篇
  2022年   25029篇
  2021年   35660篇
  2020年   26896篇
  2019年   26519篇
  2018年   29152篇
  2017年   30589篇
  2016年   35241篇
  2015年   37044篇
  2014年   53363篇
  2013年   116558篇
  2012年   67434篇
  2011年   82095篇
  2010年   73150篇
  2009年   79827篇
  2008年   72405篇
  2007年   68213篇
  2006年   71595篇
  2005年   62783篇
  2004年   56548篇
  2003年   54597篇
  2002年   52772篇
  2001年   48087篇
  2000年   46686篇
  1999年   46674篇
  1998年   51376篇
  1997年   45586篇
  1996年   41876篇
  1995年   36535篇
  1994年   33548篇
  1993年   31608篇
  1992年   28750篇
  1991年   25145篇
  1990年   24978篇
  1989年   23856篇
  1988年   22015篇
  1987年   19940篇
  1986年   19164篇
  1985年   22285篇
  1984年   22455篇
  1983年   20351篇
  1982年   19356篇
  1981年   19383篇
  1980年   18038篇
  1979年   18492篇
  1978年   17673篇
  1977年   17392篇
  1976年   18084篇
  1975年   15936篇
  1974年   15440篇
  1973年   15532篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
Wireless Personal Communications - In recent years, the emergence of Internet of things and cyber-physical system provide a proactive and efficacious solution to enable remote monitoring, machine...  相似文献   
182.
Li  Qian  Chen  Yan  Sun  Shikun  Zhu  Muyuan  Xue  Jing  Gao  Zihan  Zhao  Jinfeng  Tang  Yihe 《Water Resources Management》2022,36(12):4799-4817
Water Resources Management - Increasing water consumption in agriculture due to global climate change has posed considerable challenges to food security, thus improving the efficiency of water...  相似文献   
183.
Multimedia Tools and Applications - In this paper, a hashing based watermarking technique for the protection and authentication of document image is proposed. Message Digest 5 (MD5) hashing is...  相似文献   
184.
Ferroptosis is gaining followers as mechanism of selective killing cancer cells in a non-apoptotic manner, and novel nanosystems capable of inducing this iron-dependent death are being increasingly developed. Among them, polydopamine nanoparticles (PDA NPs) are arousing interest, since they have great capability of chelating iron. In this work, PDA NPs were loaded with Fe3+ at different pH values to assess the importance that the pH may have in determining their therapeutic activity and selectivity. In addition, doxorubicin was also loaded to the nanoparticles to achieve a synergist effect. The in vitro assays that were performed with the BT474 and HS5 cell lines showed that, when Fe3+ was adsorbed in PDA NPs at pH values close to which Fe(OH)3 begins to be formed, these nanoparticles had greater antitumor activity and selectivity despite having chelated a smaller amount of Fe3+. Otherwise, it was demonstrated that Fe3+ could be released in the late endo/lysosomes thanks to their acidic pH and their Ca2+ content, and that when Fe3+ was co-transported with doxorubicin, the therapeutic activity of PDA NPs was enhanced. Thus, reported PDA NPs loaded with both Fe3+ and doxorubicin may constitute a good approach to target breast tumors.  相似文献   
185.
At present, the development and implementation of digital transformation are the keys to promoting high-quality industry development. The new digital fabrication method of robotic 3D printing is a research area being studied by many to tackle the issue of the declining productivity of traditional construction methods. Although many studies have been done, most of the current 3D printing projects are facing limitations in terms of scale. In order to bridge the gap, this article proposed a mass customization 3D printing framework system for large-scale projects. This article discusses how mass customization is made possible through the joint operation of the FUROBOT software and 3D printing hardware. By taking the east gate of Nanjing Happy Valley Plaza as a case study, the article demonstrates and studies the feasibility of the large-scale mass customization 3D printing framework system.  相似文献   
186.
Cybernetics and Systems Analysis - The authors propose a method for solving the problem of approach of controlled objects in dynamic game problems with a terminal payoff function. The method is...  相似文献   
187.
Journal of Computer and Systems Sciences International - The solution of the problem of determining the trajectory control of the observation process of a mobile digital direction finder in the...  相似文献   
188.
Gao  Zehai  Liu  Yang  Li  Nan  Ma  Kangjie 《Water Resources Management》2022,36(8):2685-2702
Water Resources Management - Urban river not only has the important function in urban hydrological environment, but also is an area for entertainment. Water quality assessment is the core technique...  相似文献   
189.
Vieira  Elizabeth S. 《Scientometrics》2022,127(5):2747-2772

It is widely recognised that science in Africa will benefit from international research collaboration (IRC), and therefore studies have been done on IRC in Africa (hereafter: Africa-related IRC research). However, there is no information on the development of Africa-related IRC research, the geographical location of the scientists interested in the topic, the visibility of the literature and the themes researched. This information makes it possible to understand relevant aspects in the context of IRC in Africa, which are useful for identifying IRC strengths, weaknesses and opportunities. It also allows paving the way for future research on this topic. Using discipline–specific terms, bibliometric, and thematic analysis, I collected the literature on Africa-related IRC research indexed in the Web of Science Core Collection (WoS). The results showed that the number of publications on the topic has increased, few African countries have researched the topic, a third of the publications were written exclusively by African scientists, and the topic has high visibility. The panoply of publications revealed that patterns, driving factors, effects, networks, asymmetries, and policies concerning IRC were the main themes researched.

  相似文献   
190.
Marrone  Mauricio  Lemke  Sascha  Kolbe  Lutz M. 《Scientometrics》2022,127(7):3857-3878
Scientometrics - Computer-assisted methods and tools can help researchers automate the coding process of literature reviews and accelerate the literature review process. However, existing...  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