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   40篇
  免费   8篇
  国内免费   24篇
化学   57篇
晶体学   1篇
数学   7篇
物理学   7篇
  2022年   3篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2016年   3篇
  2015年   3篇
  2014年   6篇
  2013年   10篇
  2012年   4篇
  2011年   5篇
  2010年   4篇
  2009年   7篇
  2008年   8篇
  2007年   5篇
  2006年   2篇
  2005年   4篇
  2004年   3篇
  2002年   1篇
  1997年   1篇
排序方式: 共有72条查询结果,搜索用时 250 毫秒
61.
一个四核铜配合物的水热合成、结构及荧光性质   总被引:1,自引:0,他引:1  
桥联四核铜配合物;水热合成;晶体结构;荧光光谱;电子结构  相似文献   
62.
Chen HX  Zhang XX 《Electrophoresis》2008,29(16):3406-3413
The present report describes a rapid, simple, and highly selective approach to perform testosterone competitive immunoassay by CE and LIF detection. The method involves using synthesized fluorescence-labeled testosterone as a tracer to compete with testosterone. Two polyclonal antibodies (antibody (Ab) arised from T-3-BSA (Ab(3)) and Ab arised from T-17-BSA (Ab(17))) and their respective tracers have been optimized and Ab(3) system is used for the quantification of testosterone by CE-based immunoassay. The method is developed with a wide working range of 3.70-2000 ng/mL and an LOD at 1.11 ng/mL. Tests for normal and positive urine samples show that this method has the potential to be applied in testosterone doping control.  相似文献   
63.
In this paper, we consider a logistic delay equation with a linear delay harvesting term of the following form:N˙(t)=r(t)N(t)a-b0N(t)-k=1mbkN(hk(t))-l=1ncl(t)N(gl(t)),t0,N(t)=φ(t),t<0,N(0)=N0in both cases when b0=0 and b00. We present some results on the boundedness and positiveness of the solutions of this equation without the condition that N0 is upper bounded by some constant which is necessary to the corresponding results in [L. Berezansky, E. Braverman, L. Idels, Delay differential logistic equation with harvesting, Math. Comput. Modelling 40 (2004) 1509–1525], and our results extend these known results.  相似文献   
64.
本文研究了La2O3的含量对(Yb0.05 Y0.95)2O3透明激光陶瓷的结构性能和烧结性能的影响.结果表明:随着La2O3含量的增加,拉曼光谱特征峰发生红移,声子能量降低,半高宽增大,相对强度先增大后减小;同时密度、相对密度和透过率都增大,陶瓷的晶粒减小,而当La2O3含量继续增加时,晶粒基本保持不变.但适量的La2O3掺杂量对(Yb0.05Y0.95)2O3透明激光陶瓷的发射性能影响不大.最合适的La2O3添加量为10at%,最合适的烧结温度为1700℃,最后样品的直线透过率可达到75%.  相似文献   
65.
Hong-Xu Chen 《Talanta》2009,78(1):259-154
An immunoaffinity capillary column has been made with poly (2-vinyl-4, 4-dimethylazlactone-co-2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) (VDA-co-HEMA-co-EDMA) monolith as a support for the immobilized antibody. The monolith is prepared by UV-initiated in situ polymerization, followed by immobilizing anti-testosterone polyclonal antibody through the rapid reaction with VDA. Fluorescence labeled testosterone at C3 is designed as a tracer to estimate the extraction ability of this immunoaffinity column, and to optimize the immunoextraction process, such as washing, eluting, incubation and injection. The performance in a more realistic application is then demonstrated successfully for the rapid extraction of testosterone (T) by competitive immunoassay and on-line laser-induced fluorescence (LIF) detection. This immunoaffinity monolith is easily prepared, with high mechanical strength and low flow resistance. It is a satisfactory material as an immunoextractor to detect small molecular compounds specifically and rapidly with high sensitivity (sub ng/mL level).  相似文献   
66.
The thermal decomposition behavior of composite modified double-base propellant containing hexanitrohexaazaisowurtzitane (CL-20/CMDB propellant) was studied by microcalorimetry. The kinetic and thermodynamic parameters were obtained from the analysis of the heat flow curves. The effect of different proportion of CL-20 to the thermal decomposition behavior, kinetics, and thermal hazard was investigated at the same time. The critical temperature of thermal explosion (T b), the self acceleration decomposition temperature (T SADT), and the adiabatic decomposition temperature rise (??T ad) were calculated to evaluate the thermal hazard of the CL-20/CMDB propellant. It shows that the CMDB propellant with 38% CL-20 has relative lower values of E and lgA, and with 18% CL-20 has the highest potential hazard.  相似文献   
67.

Abstract  

The title compound, [Cu(C10H8N2)(HCO2)2]n, in which the asymmetric unit contains one crystallographically independent copper(II) ions, one formate and half of 4, 4′-bipy molecules, has a linear polymeric structure, with the bridging ligand 4, 4′-bipyridine connecting the CuII ions. Each ion lies on an inversion center and has a distorted octahedral environment, being coordinated by two bipy ligands and four oxygen atoms from two formate groups. The O1 in the formate group is disordered over two sites with occupancy of 0.55 and 0.45. In the crystal structure, the linear polymeric chains are linked by intermolecular C–H···O hydrogen bonds, resulting in a two-dimensional supramolecular network.  相似文献   
68.
In this paper, we present a theorem on the almost periodic solutions of second-order neutral equations with piecewise constant arguments of the form
(x(t)+px(t−1))=qx([t])+f(t),(x(t)+px(t1))=qx([t])+f(t),
where [⋅][] denotes the greatest integer function, p,qp,q (|p|>1|p|>1 or p=−1p=1) are nonzero constants, and f(t)f(t) is almost periodic.  相似文献   
69.
采用TG-DTG和DSC技术研究了含二缩三乙二醇二硝酸酯(TEGDN)和硝化甘油(NG)的混合酯、硝化棉(NC)和用作燃烧催化剂的柠檬酸镧组成的双基推进剂在常压和流动态氮气气氛下的非等温热分解反应动力学. 结果表明, 该双基推进剂的热分解过程存在2个失重阶段: 第I失重阶段为混合酯的挥发分解过程; 第II失重阶段为主放热分解反应, 机理服从三级化学反应, 减速型α-t曲线, 动力学参数: Ea=231.14 kJ·mol-1, A=1023.29 s-1, 动力学方程为dα/dt=1022.99(1-α)3 e-2.78×104/T. 由外推起始点温度(Te)和峰顶温度(Tp)计算得出该双基推进剂的热爆炸临界温度值分别为Tbe=463.62 K, Tbp=477.88 K. 反应的活化熵(⊿S)、活化焓(⊿H)和活化能(⊿G)分别为219.75 J·mol-1·K-1, 239.23 kJ·mol-1和135.96 kJ·mol-1.  相似文献   
70.
By using the method of the invariant subspaces for unbounded linear operators and Schauder??s fixed point theorem, we give an existence theorem of mild pseudo-almost periodic solutions for some semilinear differential equations with a Stepanov-like pseudo-almost periodic term under some suitable assumptions. For this purpose, we show a new composition theorem of Stepanov-like pseudo-almost periodic functions. As applications, we examine the existence of mild pseudo-almost periodic solutions to some second-order hyperbolic equations. Our work is done under a ??uniform continuity?? condition instead of the ??Lipschitz?? condition assumed in the literature.  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