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   183篇
  免费   5篇
  国内免费   2篇
化学   99篇
晶体学   4篇
力学   3篇
数学   74篇
物理学   10篇
  2024年   1篇
  2023年   2篇
  2022年   1篇
  2021年   7篇
  2020年   10篇
  2019年   5篇
  2018年   10篇
  2017年   7篇
  2016年   13篇
  2015年   8篇
  2014年   3篇
  2013年   21篇
  2012年   10篇
  2011年   18篇
  2010年   18篇
  2009年   11篇
  2008年   6篇
  2007年   2篇
  2006年   7篇
  2005年   8篇
  2004年   2篇
  2003年   2篇
  2002年   3篇
  1999年   1篇
  1998年   3篇
  1997年   2篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1990年   1篇
  1982年   1篇
排序方式: 共有190条查询结果,搜索用时 78 毫秒
81.
Let A denote the class of functions which are analytic in |z|<1 and normalized so that f(0)=0 and f′(0)=1, and let R(α, β)⊂A be the class of functions f such thatRe[f′(z)+αzf″(z)]>β,Re α>0, β<1. We determine conditions under which (i) f ∈ R(α1, β1), g ∈ R(α2, β2) implies that the convolution f×g of f and g is convex; (ii) f ∈ R(0, β1), g ∈ R(0, β2) implies that f×g is starlike; (iii) f≠A such that f′(z)[f(z)/z]μ-1 ≺ 1 + λz, μ>0, 0<λ<1, is starlike, and (iv) f≠A such that f′(z)+αzf″(z) ≺ 1 + λz, α>0, δ>0, is convex or starlike. Bibliography: 16 titles. Published inZapiski Nauchnykh Seminarov POMI, Vol. 226, 1996, pp. 138–154.  相似文献   
82.
The isomerisation of acetates from the Baylis-Hillman adducts with Mont.K10 clay-microwave combination furnished E-trisubstituted alkenes in high yield. The simple Baylis-Hillman adducts with trimethyl orthoformate and unsaturated alcohols under clay catalytic condition gave densely functionalised-isomerized products under solvent free condition. Application of the propargyl derivatives thus obtained from the isomerisation of the Baylis-Hillman adducts with propargyl alcohol has been demonstrated in the synthesis of lignan core structures by tri-n-butyltin hydride mediated vinyl radical cyclization.  相似文献   
83.
Potential Analysis - In this article, we continue our investigations of the boundary behavior of harmonic mappings. We first discuss the classical problem on the growth of radial length and obtain...  相似文献   
84.
85.
A family of 11 nitrophenol 2-nitro-5-(4-substituted phenylquinolin-2-yl)phenol derivatives (4, 4a-j) was effectively synthesized as antimicrobial medications. A mixture of the substituted 3-hydroxy-4-nitrobenzaldehyde substituted aromatic amine and substituted phenylacetylenes were used to synthesis the title compounds 4, 4a-j. Antimicrobialactivity potential of 4, 4a-j was evaluated against Streptococcus pyogenes (MTCC 442), Staphylococcus aureus (MTCC 96), Pseudomonas aeruginosa (MTCC 424), and Escherichia coli (MTCC 443). DNA gyrase inhibition studies carried out to understand the mechanism ofaction of the antimicrobial effect of target compounds. HRBC membrane stabilization (in vitro) property was also assessed as a representative human cellular cytotoxic effect of 4, 4a-j since HRBC alike lysosomal cells and the lysozyme activity leads to inflammation and its adverse effects in cellular systems. Results reveal that compounds 4c and 4h have remarkable antibacterial activity and screened for further preclinical studies.  相似文献   
86.

Activity concentration and mineralogical characterization in the intertidal sand samples of Tamilnadu coast, India have been analyzed. From the gamma spectral analysis, the average value of 238U, 232Th and 40K in the intertidal sand samples are 12 ± 4, 59 ± 4 and 197 ± 26 Bq kg−1 respectively. The average value of 232Th alone is slightly higher than the world average value. From XRD and FTIR analysis, monazite, zircon, ilmenite, magnetite, hematite, quartz, witherite, calcite, nacrite, microcline feldspar, orthoclase feldspar, gibbsite and organic carbon are identified. Of these minerals, monazite and microcline feldspar are the most associated with the presence of 232Th and 40K respectively.

  相似文献   
87.
88.
A one-pot synthesis of mono- and bis-Morita-Baylis-Hillman adducts of 1,1′-ferrocenedialdehyde has been achieved. These adducts undergo a facile and efficient stereoselective isomerization with a number of saturated, unsaturated, aromatic alcohols, phenols and thiophenol with a montmorillonite K10 clay catalyst to afford highly functionalized trisubstituted alkene derivatives of ferrocene. The synthetic utility of isomerized derivatives has been demonstrated by a ferrocene appended novel macrocycle synthesis, a ferrocenyl bis-triazole synthesis and an evaluation of the liquid crystalline property of a cholesterol derivative of ferrocene.  相似文献   
89.
A facile, high yield stereoselective synthesis of functionalized diastereomeric 3-spirocyclopropane-2-indolones (10-17a,b) from the isomerised bromo derivatives of Baylis-Hillman adducts of isatin(2-9a,b) by reductive cyclization with sodium borohydride is reported.  相似文献   
90.
Let a, b > ?1, p and q be non-zero real numbers such that p + q ≥ 1. In this paper, we study the geometric mapping properties of the (normalized) generalized polylogarithm defined in the unit disc   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