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   1533937篇
  免费   36229篇
  国内免费   11445篇
化学   668360篇
晶体学   20433篇
力学   75310篇
综合类   289篇
数学   241966篇
物理学   371271篇
无线电   203982篇
  2021年   15627篇
  2020年   18216篇
  2019年   18369篇
  2018年   13754篇
  2016年   30480篇
  2015年   22924篇
  2014年   34075篇
  2013年   80339篇
  2012年   41728篇
  2011年   37967篇
  2010年   41065篇
  2009年   46217篇
  2008年   41059篇
  2007年   37804篇
  2006年   44721篇
  2005年   36635篇
  2004年   37498篇
  2003年   35307篇
  2002年   36321篇
  2001年   34678篇
  2000年   31206篇
  1999年   28928篇
  1998年   27564篇
  1997年   27411篇
  1996年   27067篇
  1995年   24835篇
  1994年   24265篇
  1993年   23643篇
  1992年   23156篇
  1991年   23329篇
  1990年   22078篇
  1989年   21686篇
  1988年   20858篇
  1987年   19619篇
  1986年   18476篇
  1985年   25010篇
  1984年   26215篇
  1983年   22187篇
  1982年   23639篇
  1981年   22811篇
  1980年   22089篇
  1979年   21882篇
  1978年   23213篇
  1977年   22751篇
  1976年   22362篇
  1975年   21004篇
  1974年   20638篇
  1973年   21152篇
  1972年   15366篇
  1967年   13125篇
排序方式: 共有10000条查询结果,搜索用时 225 毫秒
111.
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   
112.
113.
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   
114.
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   
115.
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   
116.
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   
117.
Recently, the successful synthesis of wafer-scale single-crystal graphene, hexagonal boron nitride (hBN), and MoS2 on transition metal surfaces with step edges boosted the research interests in synthesizing wafer-scale 2D single crystals on high-index substrate surfaces. Here, using hBN growth on high-index Cu surfaces as an example, a systematic theoretical study to understand the epitaxial growth of 2D materials on various high-index surfaces is performed. It is revealed that hBN orientation on a high-index surface is highly dependent on the alignment of the step edges of the surface as well as the surface roughness. On an ideal high-index surface, well-aligned hBN islands can be easily achieved, whereas curved step edges on a rough surface can lead to the alignment of hBN along with different directions. This study shows that high-index surfaces with a large step density are robust for templating the epitaxial growth of 2D single crystals due to their large tolerance for surface roughness and provides a general guideline for the epitaxial growth of various 2D single crystals.  相似文献   
118.
Shavgulidze  N. E. 《Mathematical Notes》2021,110(1-2):297-300
Mathematical Notes -  相似文献   
119.
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   
120.
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