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   175篇
  免费   5篇
  国内免费   3篇
化学   50篇
力学   7篇
综合类   3篇
数学   74篇
物理学   49篇
  2023年   9篇
  2022年   3篇
  2021年   3篇
  2020年   4篇
  2019年   3篇
  2018年   4篇
  2017年   6篇
  2016年   6篇
  2015年   5篇
  2014年   7篇
  2013年   10篇
  2012年   7篇
  2011年   9篇
  2010年   7篇
  2009年   11篇
  2008年   11篇
  2007年   13篇
  2006年   19篇
  2005年   4篇
  2004年   7篇
  2003年   3篇
  2002年   3篇
  2001年   6篇
  2000年   3篇
  1999年   5篇
  1998年   2篇
  1997年   2篇
  1996年   4篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1982年   1篇
  1968年   1篇
排序方式: 共有183条查询结果,搜索用时 30 毫秒
31.
Manabu Oura 《Discrete Mathematics》2008,308(16):3722-3725
It is known that the weight enumerator of a self-dual doubly even code in genus g=1 can be uniquely written as an isobaric polynomial in certain homogeneous polynomials with integral coefficients. We settle the case where g=2 and prove the non-existence of such polynomials under some conditions.  相似文献   
32.
Combinatorial characterization of optimal authentication codes with arbitration was previously given by several groups of researchers in terms of affine α-resolvable + BIBDs and α-resolvable designs with some special properties, respectively. In this paper, we revisit this known characterization and restate it using a new idea of GOB designs. This newly introduced combinatorial structure simplifies the characterization, and enables us to extend Johansson’s well-known family of optimal authentication codes with arbitration to any finite projective spaces with dimension greater than or equal to 3.  相似文献   
33.
GroupCodesDefinedonTotallyOrderedSetsWanZhexian(万哲先)(InstituteofSystemsScience,AcademiaSinica,Beijing,100080andDepartmentofIn...  相似文献   
34.
设W\-m(R)是有限局部环R=Z/p\+kZ上所有m阶交错矩阵所构成的集合(p是素数,k>1). 该文通过确定R上任意m阶交错矩阵的标准形,计算出W\-m(R)在线性群GL\-m(R)作用下的轨道数及n(2r,2t,\{r\-1,\:,r\-1\}[TXX}][DD(X]s\-1[DD)],\:,\{r\-l,\:,r\-l\}[TXX}][DD(X]s\-l[DD)]),其中W(2r,2t,\{r\-1,\:,r\-1\}[TXX}][DD(X]s\-1[DD)],\:,\{r\-l,\:,r\-l\}[TXX}][DD(X]s\-l[DD)])(∑[DD(]l[]i=1[DD)]s\-i=t)表示不变因子为(2r,2t,\{r\-1,\:,r\-1\}[TXX}][DD(X]s\-1[DD)],\:,\{r\-l,\:,r\-l\}[TXX}][DD(X]s\-l[DD)])的所有m阶交错矩阵构成的集合,n(2r,2t,(2r,2t,\{r\-1,\:,r\-1\}[TXX}][DD(X]s\-1[DD)],\:,\{r\-l,\:,r\-l\}[TXX}][DD(X]s\-l[DD)])表示其中的元素个数. 最后,作者利用有限局部环R上交错矩阵的标准形构作了一个Cartesian认证码,并计算出其全部参数.  相似文献   
35.
《Discrete Mathematics》2020,343(6):111815
The intersection enumerator and the Jacobi polynomial in an arbitrary genus for a binary code are introduced. Adding the weight enumerator into our discussion, we give the explicit relations among them and give some of their basic properties.  相似文献   
36.
《Analytical letters》2012,45(15):3131-3141
ABSTRACT

Principal Component Analysis (PCA) was applied to a set of physico-chemical variables obtained from 41 samples of summer orange juice, in order to reduce the number of variables. Working with the covariance matrix, three components (which explained 98.27% of the variance) were taken. With the correlation matrix, four components which explained: 85.65% of the variance were taken. With the scores corresponding to both matrixes a principal component regression (PCR) was carried out against the dependent variable of Brix grades, so as to obtain two statistical models that would allow the detection of adulterations in pure orange juice, based on dilution and later masking by the addition of sugar. The models were tested with simulated dilutions of 41 samples of juice, to assess the effectiveness of each for the detection of adulterations. Both models turned out to be equally effective, detecting adulterations starting from about 15 % of dilution.  相似文献   
37.
38.
39.
40.
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