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   23篇
  免费   0篇
  国内免费   4篇
化学   5篇
数学   21篇
物理学   1篇
  2022年   4篇
  2019年   1篇
  2018年   3篇
  2017年   2篇
  2016年   1篇
  2014年   4篇
  2009年   1篇
  2006年   1篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1999年   5篇
  1998年   2篇
排序方式: 共有27条查询结果,搜索用时 31 毫秒
1.
An effective and environmentally benign procedure for the synthesis of isoxazolines and isoxazoles has been developed by a cycloaddition of nitrile oxides with alkenes or alkynes in water. In this approach, potassium chloride is first oxidized into chlorine in water by the environmentally friendly oxidant Oxone®, then aldoximes are oxidized into nitrile oxides by the in situ generated hypochlorous acid, finally a 1,3-dipolar cycloaddition between nitrile oxides and alkenes or alkynes occurs to provide the corresponding isoxazolines and isoxazoles in good yields.  相似文献   
2.
In this paper we obtain exact rates of uniform convergence for oscillation moduli and Lipschitz-1/2 moduli of PL-process and cumulative hazard process when the data are subject to left truncation and right censorship. Based on these results, the exact rates of uniform convergence for various types of density and hazard function estimators are derived. Research supported by the Postdoctoral Programme Foundation and the National Natural Science Foundation of China  相似文献   
3.
1991MRSubjectClassification62G05,62E201IntroductionandtheMainResultsInthisarticlewestudysllrvivaldatawhicharesubjecttobothlefttrull(:ationandrightcensoring(LTRC).Morespecifically,let(X,T,Y)denoterandomvariableswhereXisthevariableofinterest,calledthelifetimevariable,withunknowndistributionfullctioll(d.f.)F;Tistherandomlefttruncatiolltiliiewitharbitraryd.f.G,andYistherandorl.1rightcensoringtirliewitharbitraryd.f.H.ItisassumedthatX,T,Yarerxlutuallyindependent.Intheran相似文献   
4.
Let c?k(n) be the number of k-colored generalized Frobenius partitions of n. We establish some infinite families of congruences for c?3(n) and c?9(n) modulo arbitrary powers of 3, which refine the results of Kolitsch. For example, for k3 and n0, we prove that
c?3(32kn+7?32k+18)0(mod34k+5).
We give two different proofs to the congruences satisfied by c?9(n). One of the proofs uses a relation between c?9(n) and c?3(n) due to Kolitsch, for which we provide a new proof in this paper.  相似文献   
5.
随机删失数据下核密度估计的Berry-Esseen界   总被引:2,自引:0,他引:2  
孙六全  朱力行 《数学学报》1999,42(4):627-636
本文在随机删失数据下研究了概率密度函数的核估计,获得了此核估计的一个Berry-Esseen界.  相似文献   
6.
Jin  Jin  Ye  Peng  Sun  Liuquan 《中国科学 数学(英文版)》2022,65(3):583-602

Missing covariate data arise frequently in biomedical studies. In this article, we propose a class of weighted estimating equations for the additive hazard regression model when some of the covariates are missing at random. Time-specific and subject-specific weights are incorporated into the formulation of weighted estimating equations. Unified results are established for estimating selection probabilities that cover both parametric and non-parametric modeling schemes. The resulting estimators have closed forms and are shown to be consistent and asymptotically normal. Simulation studies indicate that the proposed estimators perform well for practical settings. An application to a mouse leukemia study is illustrated.

  相似文献   
7.
Let b(n) be the number of cubic partition pairs of n. We establish three congruences for b(n) modulo arbitrary powers of 3. Meanwhile, we prove some conjectures proposed by the first author.  相似文献   
8.
Wang  Liuquan  Yang  Yifan 《The Ramanujan Journal》2022,59(3):831-882
The Ramanujan Journal - We develop an approach to establish $$1/\pi $$ -series from bimodular forms. Utilizing this approach, we obtain new families of 2-variable $$1/\pi $$ -series associated to...  相似文献   
9.
With 1,1,1-trifluoro-2-iodoethane as catalyst, a novel and efficient procedure has been developed for preparation of α-tosyloxyketones from ketones. In this protocol, 1,1,1-trifluoro-2-iodoethane is first oxidized by m-chloroperbenzoic acid to a hypervalent iodine intermediate. The in situ–generated active iodine species then reacts with ketones to afford the corresponding α-tosyloxyketones in good yields.  相似文献   
10.
孙六全  周勇 《数学学报》1998,41(5):1113-1120
本文在左截断右删失模型下获得了乘积限过程和累积失效率过程的振动模和Lipschitz-12模的强一致收敛的精确速度.作为定理的应用,推导了各种核密度估计和失效率估计的强一致收敛的精确速度.  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