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   1761285篇
  免费   47747篇
  国内免费   17225篇
电工技术   49047篇
技术理论   31篇
综合类   23289篇
化学工业   314926篇
金属工艺   79135篇
机械仪表   59645篇
建筑科学   67949篇
矿业工程   20699篇
能源动力   57485篇
轻工业   128466篇
水利工程   19532篇
石油天然气   56002篇
武器工业   2358篇
无线电   223695篇
一般工业技术   312368篇
冶金工业   173369篇
原子能技术   36520篇
自动化技术   201741篇
  2022年   15836篇
  2021年   26138篇
  2020年   19565篇
  2019年   21091篇
  2018年   22678篇
  2017年   22939篇
  2016年   28218篇
  2015年   27775篇
  2014年   41603篇
  2013年   102687篇
  2012年   52052篇
  2011年   65308篇
  2010年   57665篇
  2009年   65254篇
  2008年   58681篇
  2007年   55409篇
  2006年   59479篇
  2005年   52299篇
  2004年   49449篇
  2003年   48288篇
  2002年   46915篇
  2001年   43157篇
  2000年   42269篇
  1999年   42545篇
  1998年   49681篇
  1997年   43630篇
  1996年   39969篇
  1995年   34721篇
  1994年   32174篇
  1993年   30787篇
  1992年   28139篇
  1991年   24783篇
  1990年   24691篇
  1989年   23560篇
  1988年   21980篇
  1987年   19951篇
  1986年   19273篇
  1985年   22530篇
  1984年   22582篇
  1983年   20544篇
  1982年   19425篇
  1981年   19489篇
  1980年   18064篇
  1979年   18655篇
  1978年   17795篇
  1977年   17606篇
  1976年   18632篇
  1975年   16050篇
  1974年   15601篇
  1973年   15658篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Elevated activation of the autophagy pathway is currently thought to be one of the survival mechanisms allowing therapy-resistant cancer cells to escape elimination, including for cytarabine (AraC)-resistant acute myeloid leukemia (AML) patients. Consequently, the use of autophagy inhibitors such as chloroquine (CQ) is being explored for the re-sensitization of AraC-resistant cells. In our study, no difference in the activity of the autophagy pathway was detected when comparing AraC-Res AML cell lines to parental AraC-sensitive AML cell lines. Furthermore, treatment with autophagy inhibitors CQ, 3-Methyladenine (3-MA), and bafilomycin A1 (BafA1) did not re-sensitize AraC-Res AML cell lines to AraC treatment. However, in parental AraC-sensitive AML cells, treatment with AraC did activate autophagy and, correspondingly, combination of AraC with autophagy inhibitors strongly reduced cell viability. Notably, the combination of these drugs also yielded the highest level of cell death in a panel of patient-derived AML samples even though not being additive. Furthermore, there was no difference in the cytotoxic effect of autophagy inhibition during AraC treatment in matched de novo and relapse samples with differential sensitivity to AraC. Thus, inhibition of autophagy may improve AraC efficacy in AML patients, but does not seem warranted for the treatment of AML patients that have relapsed with AraC-resistant disease.  相似文献   
52.
To investigate the evolution of the structural and enhanced magnetic properties of GdMnO3 systems induced by the substitution of Mn with Cr, polycrystalline GdMn1-xCrxO3 samples were synthesized via solid-state reactions. XRD characterization shows that all GdMn1-xCrxO3 compounds with single-phase structures crystallize well and that Cr3+ ions entering the lattice sites of GdMnO3 induce structural distortion. SEM results indicate that the grain size of the synthesized samples (a few microns) decreases as the Cr substitution concentration increases. Positron annihilation lifetime spectroscopy reveals that vacancy-type defects occur in GdMn1-xCrxO3 ceramics and that the vacancy size and concentration clearly change with the Cr content. The temperature and field dependence of the magnetization curves show that Cr substitution significantly influences the magnetic ordering of the gadolinium sublattice, improving the weak ferromagnetic transition temperature and magnetization of GdMn1-xCrxO3. The enhanced magnetization of GdMn1-xCrxO3 is closely related to the vacancy defect concentration.  相似文献   
53.
Multidimensional Systems and Signal Processing - Non-local means (NLM) method is a powerful technique in the field of image processing. The center weight CW (the weight of the pixel to be denoised)...  相似文献   
54.
Wireless Personal Communications - Besides anti-malware usage for the eradication of malicious attacks, researchers have developed epidemic models in order to gain more insights into the spread...  相似文献   
55.
Telecommunication Systems - Energy saving in User Equipment (UE) is one of the important issues for limited sources of power in the device. It is critical for the UE to maximize its energy...  相似文献   
56.
Semiconductors - Abstract—In our work, we carry out a structural-spectroscopic study of AlGaN/GaN epitaxial layers grown by molecular-beam epitaxy with nitrogen-plasma activation on a hybrid...  相似文献   
57.
Journal of Communications Technology and Electronics - A new design of wavelets based on the convolution of a compactly supported function with a rectangular pulse is proposed and theoretically...  相似文献   
58.
Journal of Communications Technology and Electronics - A statistical study of the effectiveness of the non-threshold search procedure for a noise-like phase-shift keyed signal by the delay time is...  相似文献   
59.
Journal of Communications Technology and Electronics - In recent years, there has been a rapid improvement in photonics products due to the use of multilayer heterostructures grown on the basis of...  相似文献   
60.
Mobile Networks and Applications - Project MindCatcher is an art/research project which has the intention to explore the potential of interactive artistic environments for measuring and a better...  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