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   53篇
  免费   0篇
  国内免费   3篇
化学   18篇
力学   1篇
数学   34篇
物理学   3篇
  2023年   1篇
  2022年   3篇
  2021年   1篇
  2020年   2篇
  2019年   1篇
  2018年   2篇
  2013年   1篇
  2012年   1篇
  2011年   2篇
  2009年   4篇
  2008年   4篇
  2007年   4篇
  2006年   5篇
  2005年   6篇
  2004年   2篇
  2003年   1篇
  2002年   2篇
  2001年   1篇
  2000年   4篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1986年   1篇
排序方式: 共有56条查询结果,搜索用时 203 毫秒
41.
《印度化学会志》2021,98(7):100088
Bitter principles of neem oil have proven activity against agricultural pests. The neem oil is also reported for its potential insecticidal and mosquito repellency properties. As active principles of a non-edible neem oil cannot be separated from oil itself, formulating microemulsions of neem oil have a promising future. Microemulsions are preferred over conventionally used pesticide systems like for their long-term thermodynamic stability, safety, low viscosity, cost economy and aesthetic appeal. A pseudo ternary diagram is a convenient way of determining the compositions of the stable microemulsions and macroemulsions. By identifying specific regions in such plots, possible economical compositions can be determined. Such compositions use optimum quantities of surfactants. Moreover, our molecular docking analysis of an active principles of neem oil against odorant binding proteins, viz. 3N7H and 3Q8I suggested that compound, nimbin had higher binding affinities towards OBPs with docking scores of −87.4861 and −105.696 ​kcal/mol than their corresponding reference ligands. Thus, for a safer, an effective and an economical designing and developments of natural mosquito repellents, this study can be considered useful.  相似文献   
42.
认为S的每个元素都诱导了S-系上的一个一元运算,因此S-系是有限代数,泛代数中的所有概念都是适用的.定义了S-系的可半格化子集和S-系的子集的面,构建了逆半群上的S一系的内射壳.推广了有关文献中的结果.  相似文献   
43.
We completely describe lattice convex polytopes in ℝ n (for any dimension n) that are regular with respect to the group of affine transformations preserving the lattice. Supported in part by the RFBR (Grant Nos. SS-1972.2003.1 and 05-01-01012a) and the NWO-RFBR (Grant No. 047.011.2004.026/RFBR No. 05-02-89000-NWO_a).  相似文献   
44.
Let (xn) be an isometric interpolating sequence or a sequence of trivial points in the spectrum of H. It is shown that either every cluster point of that sequence has a maximal support set or there exists yM(H+C) such that the support of xn is contained in the support of y for infinitely many n. Similar results for Gleason parts are obtained, too. We also investigate the H‐convex hulls of countable unions of support sets and show that whenever supp x ? supp y and x /∈ , then the H‐convex hull of supp x does not meet . (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
45.
Error estimates for the error reproducing kernel method (ERKM) are provided. The ERKM is a mesh-free functional approximation scheme [A. Shaw, D. Roy, A NURBS-based error reproducing kernel method with applications in solid mechanics, Computational Mechanics (2006), to appear (available online)], wherein a targeted function and its derivatives are first approximated via non-uniform rational B-splines (NURBS) basis function. Errors in the NURBS approximation are then reproduced via a family of non-NURBS basis functions, constructed using a polynomial reproduction condition, and added to the NURBS approximation of the function obtained in the first step. In addition to the derivation of error estimates, convergence studies are undertaken for a couple of test boundary value problems with known exact solutions. The ERKM is next applied to a one-dimensional Burgers equation where, time evolution leads to a breakdown of the continuous solution and the appearance of a shock. Many available mesh-free schemes appear to be unable to capture this shock without numerical instability. However, given that any desired order of continuity is achievable through NURBS approximations, the ERKM can even accurately approximate functions with discontinuous derivatives. Moreover, due to the variation diminishing property of NURBS, it has advantages in representing sharp changes in gradients. This paper is focused on demonstrating this ability of ERKM via some numerical examples. Comparisons of some of the results with those via the standard form of the reproducing kernel particle method (RKPM) demonstrate the relative numerical advantages and accuracy of the ERKM.  相似文献   
46.
The translational hull of a strongly right type-A semigroup   总被引:2,自引:0,他引:2  
It is proved that the translational hull of a strongly right type-A (C-rpp) semigroup is itself a strongly right type-A(C-rpp) semigroup.  相似文献   
47.
This paper provides some useful results for convex risk measures. In fact, we consider convex functions on a locally convex vector space E which are monotone with respect to the preference relation implied by some convex cone and invariant with respect to some numeraire (‘cash’). As a main result, for any function f, we find the greatest closed convex monotone and cash-invariant function majorized by f. We then apply our results to some well-known risk measures and problems arising in connection with insurance regulation.  相似文献   
48.
Convex Hulls in Singular Spaces of Negative Curvature   总被引:1,自引:0,他引:1  
The paper gives a simple example of a complete CAT(–1)-space containing a set S with the following property: the boundary at infinity CH(S)of the convex hull of S differs from S by an isolated point. In contrast to this it is shown that if S is a union of finitely many convex subsets of a complete CAT(–1)-space X, then CH(S) = S. Moreover, this identity holds without restrictions on S if CH is replaced by some notion of almost convex hull.  相似文献   
49.
This article considers coherent frame homomorphisms h : LM between coherent frames, which induce an isomorphism between the boolen frames of polars, with M projectable, and such that M is generated by h(L) and certain complemented elements of M. This abstracts the passage from a semiprime commutative ring with identity to its projectable hull. The frame theoretic setting is investigated thoroughly, first without any assumptions beyond the Zermelo–Fraenkel axioms of set theory, and, subsequently, assuming that algebraic frames are spatial. The culmination of this effort is the result that the spectrum of d-elements of M is obtained from that of L by refining the given hull–kernel topology to the patch topology. The second part of the article relates the projectable hull to the (von Neumann) regular hull, in a variety of contexts, including that of f-rings. For a uniformly complete f-algebra A, it is shown that the maximal ℓ-ideals of A that are traces of real maximal ideals of the regular hull HA are precisely the almost P-points of the space of maximal ℓ-ideals of A. For Bernhard Banaschewski, on the occasion of his 80th birthday.  相似文献   
50.
The paper deals with a thorough investigation on the antimicrobial activity of RF oxygen plasma and Azadirachtin (neem extract) treated cotton fabric. The hydrophilicity of cotton fabric was found to improve when treated with RF oxygen plasma. The process parameters such as electrode gap, time of exposure and oxygen pressure have been varied to study their effect on improving the hydrophilicity of the cotton fabric. The static immersion test has been carried out to assess the hydrophilicity of the oxygen plasma treated samples and the process parameters were optimized based on these test results. The formation of carbonyl group during surface modification in the plasma treated sample was analysed using FTIR studies. The surface morphology has been studied using SEM micrographs.The antimicrobial activity was imparted to the RF oxygen plasma treated samples using methanolic extract of neem leaves containing Azadirachtin. The antimicrobial activity of these samples has been analysed and compared with the activity of the cotton fabric treated with neem extract alone. The investigation reveals that the surface modification due to RF oxygen plasma was found to increase the hydrophilicity and hence the antimicrobial activity of the cotton fabric when treated with Azadirachtin.  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