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   1654298篇
  免费   44606篇
  国内免费   18111篇
化学   737448篇
晶体学   20955篇
力学   79926篇
综合类   434篇
数学   252193篇
物理学   405458篇
无线电   220601篇
  2021年   17984篇
  2020年   20343篇
  2019年   20555篇
  2018年   17642篇
  2017年   15792篇
  2016年   33845篇
  2015年   25526篇
  2014年   37311篇
  2013年   84502篇
  2012年   50013篇
  2011年   49386篇
  2010年   46671篇
  2009年   50987篇
  2008年   49694篇
  2007年   46558篇
  2006年   51165篇
  2005年   43282篇
  2004年   42798篇
  2003年   39606篇
  2002年   39968篇
  2001年   39541篇
  2000年   34656篇
  1999年   31573篇
  1998年   29357篇
  1997年   29029篇
  1996年   28550篇
  1995年   26049篇
  1994年   25390篇
  1993年   24501篇
  1992年   24490篇
  1991年   24481篇
  1990年   23199篇
  1989年   22629篇
  1988年   21775篇
  1987年   20430篇
  1986年   19255篇
  1985年   25663篇
  1984年   26645篇
  1983年   22477篇
  1982年   23831篇
  1981年   22998篇
  1980年   22237篇
  1979年   22224篇
  1978年   23386篇
  1977年   22970篇
  1976年   22576篇
  1975年   21253篇
  1974年   20879篇
  1973年   21342篇
  1972年   15537篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
121.
Journal of Applied Spectroscopy - Detailed measurements of nonlinear optical properties and optical limiting for four phthalocyanine (Pc) derivatives (PcCo, PcCu, PcMn, and PcSi) are reported. The...  相似文献   
122.
123.
Physics of Atomic Nuclei - The muon puzzle is an excess of muon bundles generated by primary cosmic rays (PCR) at energies above 10 $${}^{17}$$ eV compared to estimations that assume even a heavy...  相似文献   
124.
Taherian  A.  Toutounian  F. 《Numerical Algorithms》2021,88(4):1831-1850
Numerical Algorithms - In this paper, the block generalized product-type bi-conjugate gradient (GPBi-CG) method for solving large, sparse nonsymmetric linear systems of equations with multiple...  相似文献   
125.
Mobile Networks and Applications - Blockchain applications have continuously improved ever since its first debut on cryptocurrency. From then on, its uses have branched out from the financial...  相似文献   
126.
Journal of Signal Processing Systems - Convolutional Neural Networks (CNNs) have improved several computer vision applications, like object detection and classification, when compared to other...  相似文献   
127.
Utilizing inner-crystal piezoelectric polarization charges to control carrier transport across a metal-semiconductor or semiconductor–semiconductor interface, piezotronic effect has great potential applications in smart micro/nano-electromechanical system (MEMS/NEMS), human-machine interfacing, and nanorobotics. However, current research on piezotronics has mainly focused on systems with only one or rather limited interfaces. Here, the statistical piezotronic effect is reported in ZnO bulk composited of nanoplatelets, of which the strain/stress-induced piezo-potential at the crystals’ interfaces can effectively gate the electrical transport of ZnO bulk. It is a statistical phenomenon of piezotronic modification of large numbers of interfaces, and the crystal orientation of inner ZnO nanoplatelets strongly influence the transport property of ZnO bulk. With optimum preferred orientation of ZnO nanoplatelets, the bulk exhibits an increased conductivity with decreasing stress at a high pressure range of 200–400 MPa, which has not been observed previously in bulk. A maximum sensitivity of 1.149 µS m−1 MPa−1 and a corresponding gauge factor of 467–589 have been achieved. As a statistical phenomenon of many piezotronic interfaces modulation, the proposed statistical piezotronic effect extends the connotation of piezotronics and promotes its practical applications in intelligent sensing.  相似文献   
128.
Fullerenes are candidates for theranostic applications because of their high photodynamic activity and intrinsic multimodal imaging contrast. However, fullerenes suffer from low solubility in aqueous media, poor biocompatibility, cell toxicity, and a tendency to aggregate. C70@lysozyme is introduced herein as a novel bioconjugate that is harmless to a cellular environment, yet is also photoactive and has excellent optical and optoacoustic contrast for tracking cellular uptake and intracellular localization. The formation, water-solubility, photoactivity, and unperturbed structure of C70@lysozyme are confirmed using UV-visible and 2D 1H, 15N NMR spectroscopy. The excellent imaging contrast of C70@lysozyme in optoacoustic and third harmonic generation microscopy is exploited to monitor its uptake in HeLa cells and lysosomal trafficking. Last, the photoactivity of C70@lysozyme and its ability to initiate cell death by means of singlet oxygen (1O2) production upon exposure to low levels of white light irradiation is demonstrated. This study introduces C70@lysozyme and other fullerene-protein conjugates as potential candidates for theranostic applications.  相似文献   
129.
Shavgulidze  N. E. 《Mathematical Notes》2021,110(1-2):297-300
Mathematical Notes -  相似文献   
130.
Russian Physics Journal - The specific features of the sorption activity of silver nanoparticles (AgNPs) on biodegradable polymers of natural (collagen) and artificial (polyamide 6.6) origin have...  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