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   8179篇
  免费   404篇
  国内免费   55篇
化学   6086篇
晶体学   79篇
力学   161篇
数学   636篇
物理学   1676篇
  2023年   44篇
  2022年   100篇
  2021年   171篇
  2020年   148篇
  2019年   158篇
  2018年   116篇
  2017年   127篇
  2016年   276篇
  2015年   233篇
  2014年   308篇
  2013年   512篇
  2012年   636篇
  2011年   676篇
  2010年   436篇
  2009年   380篇
  2008年   563篇
  2007年   495篇
  2006年   482篇
  2005年   387篇
  2004年   335篇
  2003年   298篇
  2002年   321篇
  2001年   172篇
  2000年   177篇
  1999年   95篇
  1998年   80篇
  1997年   78篇
  1996年   83篇
  1995年   71篇
  1994年   40篇
  1993年   51篇
  1992年   49篇
  1991年   34篇
  1990年   40篇
  1989年   43篇
  1988年   19篇
  1987年   23篇
  1986年   20篇
  1985年   30篇
  1984年   25篇
  1983年   24篇
  1982年   22篇
  1981年   18篇
  1979年   16篇
  1978年   20篇
  1977年   22篇
  1976年   19篇
  1975年   14篇
  1973年   14篇
  1970年   18篇
排序方式: 共有8638条查询结果,搜索用时 812 毫秒
921.
Novel ZnO/TiO(2) composite nanofibers were fabricated by an electrospinning method and showed excellent antimicrobial activity against gram-negative Escherichia coli and gram-positive Staphylococcus aureus under UV irradiation and in the absence of light.  相似文献   
922.
Photochromic compound-conjugated fluorescent fullerene-silica nanoparticles prepared by the reverse-microemulsion method was utilized for photoswitchable cellular imaging by repeatable irradiation of ultraviolet and visible light.  相似文献   
923.
A highly processable, new semiconducting polymer, PCDTTz, based on alternating thiazolothiazole and carbazole units was synthesized. The new polymer exhibited a field-effect carrier mobility of up to 3.8 × 10(-3) cm(2) V(-1) s(-1) and bulk heterojunction solar cells made from PCDTTz produced a power conversion efficiency of 4.88% under AM 1.5 G (100 mW cm(-2)) conditions.  相似文献   
924.
We report charge-switching ionic nanocomplexes comprised of glycol chitosan grafted with 2,3-dimethylmaleic acid (DMA) (denoted as 'GCS-g-DMA' hereafter) and a proapoptotic peptide. This system allowed for improved peptide delivery to tumor sites via a mechanism of selective peptide release when the pH was dropped from 7.4 to 6.8.  相似文献   
925.
Endosome-escapable poly(amino acid) nanoparticles composed of iron oxide nanocrystals and anticancer drugs were prepared and demonstrated high T(2) relaxivity coefficients and higher efficacy attributed to the endosomolytic ability of the conjugated histidine moiety.  相似文献   
926.
Micron thick, well-organized mesoporous TiO(2) films with high porosity and good connectivity were synthesized by templating an amphiphilic graft copolymer for solid-state dye-sensitized solar cells.  相似文献   
927.
For the first time, employment of nicotinamide coenzyme NAD analogs has overcome the limitations of NAD in electrochemical regeneration. It has been shown that NAD analogs, APAD and PAAD, were electrochemically reduced more efficiently than original NAD and that the stability of their reduced products was also much higher than NADH.  相似文献   
928.
Shewanella oneidensis MR-1 rapidly accumulates long, extracellular, U(VI) nanowires composed of polycrystalline chains of discrete meta-schoepite (UO(3)·2H(2)O) nanocrystallites. The production of uranium(VI) nanowires could provide a novel strategy for remediation of uranium contamination in sediments and aquifers, as well as the recovery of uranium in manufacturing processes.  相似文献   
929.
Two-dimensional enantiomers arising from an achiral oligomer form two-dimensional crystals that simultaneously display random mixing along one axis and periodic order along the other axis. This chirality behavior is interpreted in the contexts of kinetics and thermodynamics and considered as a mechanism for eroded enantioenrichment during recrystallization of scalemic mixtures.  相似文献   
930.
A new pyrene-cored π-conjugated molecule has been synthesized through Sonogashira coupling reaction. The single-crystalline microribbon-based FET exhibited the highest mobility of 0.7 cm(2) V(-1) s(-1) (I(on)/I(off) > 10(6)). Single-crystalline microribbons were employed to operate in an organic phototransistor (OPT) under very low light intensity (I = 5.6 μW cm(-2)).  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