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排序方式: 共有249条查询结果,搜索用时 46 毫秒
1.
Zhao Xuelei 《数学年刊B辑(英文版)》1997,18(1):47-54
GIRSANOV’STHEOREMONABSTRACTWIENERSPACESZHANGYINNANAbstractLet(E,H,μ)beanabstractWienerspaceinthesenseofL.Gros.Itisprovedth... 相似文献
2.
We consider the semilinear Cauchy problem for a class of pseudo-differential operators generating sub-Markovian semigroups.
Solutions of such problems with negative definite nonlinearity play an important role in constructing branching measure-valued
processes. We establish local existence and uniqueness of solutions in the context of the Dirichlet space associated to the
problem. Comparison and global properties of solutions are also studied.
Accepted 29 August 2001. Online publication 17 December 2001. 相似文献
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A.I. Olemskoi O.V. Yushchenko V.N. Borisyuk T.I. Zhilenko Yu.O. Kosminska V.I. Perekrestov 《Physica A》2012
A novel mechanism of new phase formation is studied both experimentally and theoretically in the example of quasi-equilibrium stationary condensation in an ion–plasma sputterer. Copper condensates are obtained to demonstrate that a specific network structure is formed as a result of self-assembly in the course of deposition. The fractal pattern related is inherent in the phenomena of diffusion limited aggregation. Condensate nuclei are shown to form statistical ensemble of hierarchically subordinated objects distributed in ultrametric space. The Langevin equation and the Fokker–Planck equation related are found to describe stationary distribution of thermodynamic potential variations at condensation. Time dependence of the formation probability of branching structures is found to clarify the experimental situation. 相似文献
6.
Theoretical Investigations on Photodissociation Dynamics of Deuterated Alkyl Halides CD3CH2F
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The product branching ratio between different products in multichannel reactions is as important as the overall rate of reaction, both in terms of practical applications (\emph{e.g}. models of combustion or atmosphere chemistry) in understanding the fundamental mechanisms of such chemical reactions. A global ground state potential energy surface for the dissociation reaction of deuterated alkyl halide CD\begin{document}$ _3 $\end{document} CH\begin{document}$ _2 $\end{document} F was computed at the CCSD(T)/CBS//B3LYP/aug-cc-pVDZ level of theory for all species. The decomposition of CD\begin{document}$ _3 $\end{document} CH\begin{document}$ _2 $\end{document} F is controversial concerning C\begin{document}$ - $\end{document} F bond dissociation reaction and molecular (HF, DF, H\begin{document}$ _2 $\end{document} , D\begin{document}$ _2 $\end{document} , HD) elimination reaction. Rice-Ramsperger-Kassel-Marcus (RRKM) calculations were applied to compute the rate constants for individual reaction steps and the relative product branching ratios for the dissociation products were calculated using the steady-state approach. At the different energies studied, the RRKM method predicts that the main channel for DF or HF elimination from 1, 2-elimination of CD\begin{document}$ _3 $\end{document} CH\begin{document}$ _2 $\end{document} F is through a four-center transition state, whereas D\begin{document}$ _2 $\end{document} or H\begin{document}$ _2 $\end{document} elimination from 1, 1-elimination of CD\begin{document}$ _3 $\end{document} CH\begin{document}$ _2 $\end{document} F occurs through a direct three-center elimination. At 266, 248, and 193 nm photodissociation, the main product CD\begin{document}$ _2 $\end{document} CH\begin{document}$ _2 $\end{document} +DF branching ratios are computed to be 96.57%, 91.47%, and 48.52%, respectively; however, at 157 nm photodissociation, the product branching ratio is computed to be 16.11%. Based on these transition state structures and energies, the following photodissociation mechanisms are suggested: at 266, 248, 193 nm, CD\begin{document}$ _3 $\end{document} CH\begin{document}$ _2 $\end{document} F\begin{document}$ \rightarrow $\end{document} absorption of a photon\begin{document}$ \rightarrow $\end{document} TS5\begin{document}$ \rightarrow $\end{document} the formation of the major product CD\begin{document}$ _2 $\end{document} CH\begin{document}$ _2 $\end{document} +DF; at 157 nm, CD\begin{document}$ _3 $\end{document} CH\begin{document}$ _2 $\end{document} F\begin{document}$ \rightarrow $\end{document} absorption of a photon\begin{document}$ \rightarrow $\end{document} D/F interchange of TS1\begin{document}$ \rightarrow $\end{document} CDH\begin{document}$ _2 $\end{document} CDF\begin{document}$ \rightarrow $\end{document} H/F interchange of TS2\begin{document}$ \rightarrow $\end{document} CHD\begin{document}$ _2 $\end{document} CHDF\begin{document}$ \rightarrow $\end{document} the formation of the major product CHD\begin{document}$ _2 $\end{document} +CHDF. 相似文献
7.
本文对HOC2H3F可能解离通道的势能面进行从头算CCSD(T)/CBS//B3LYP/6-311G(d,p)计算,同时对速率常数进行Rice-Ramsperger-Kassel-Marcus计算. 生成主要产物CH2CHO+HF最有利的反应途径是OHC2H3F→i2→TS14→i6→TS9→i3→TS3→CH2CHO+HF,其中速率决定步骤是HF通过TS11从CO桥接位置解离,能量比反应物高3.8 kcal/mol. 借助中间态TS14,F原子从Cα迁移到Cβ位置生成CH2O+CH2F,然后通过中间态TS16,H从O迁移到Cα位置;通过中间态TS5,C-C键断裂生成产物,其能量比反应物低1.8 kcal/mol,比TS11低4.0 kcal/mol. 相似文献
8.
合成了4种α-二亚胺镍催化剂Ar—NC(R1)C(R2)N—ArNiBr2[Ar=2,6-dimethylphenyl,R1=CnH2n+1,R2=CmH2m+1;其中Cat1:m=1,n=1;Cat2:m=2,n=1;Cat3:m=3,n=1;Cat4:m=2,n=2],考察了聚合温度、催化剂浓度和催化剂配体骨架碳原子上烷基取代基对乙烯聚合反应活性、聚合物链结构和结晶性能的影响.实验发现,当配体骨架上烷基取代基R1和R2不同时,催化剂具有较高的活性,且聚合物分子量也较高;其中,Cat2和Cat3在20℃,乙烯常压和5.8mmol/L催化剂用量下,乙烯聚合活性达1.86×103kgPE/(molNi.h)和1.92×103kgPE/(molNi.h),聚合物分子量(Mw)达6.82×105和1.019×105.聚乙烯链结构分析表明,甲基支链在聚乙烯支链中占主导地位,支化度主要受反应温度的影响;同时还发现,配体骨架碳原子上烷基取代基不同的二亚胺镍催化合成聚乙烯的长支链比例相对较高,特别是在较高反应温度40℃下,己基及以上长支链比例明显增加. 相似文献
9.
本文研究了Rb(5^2P) He(Ar) nhv→Rb(7^2D) He(Ar) n-1)hv过程,激光频率调离Rb7D5/2→5P3/2跃迁谱线20-100cm^-1,测量了精细结构普线强度分支出I(7D3/2→5P1/2)/I(7D5/2→5P3/2)。测量结果表明,原相互作用势和非绝热效应在分子离解动力学中起关键作用。 相似文献
10.
《Physics and Chemistry of Liquids》2012,50(4):321-326
Abstract The optical absorption spectra of Nd3+ ion in glutamic, L-aspartic and maleic acids in UV-VIS and NIR regions have been recorded. From the spectral data thus obtained, various spectroscopic parameters are evaluated. The radiative lifetimes (γR) and branching ratios (β) for the excited states of Nd3+ ion in three acids have been computed. The relationship between the environment sensitive Judd-Ofelt parameter (ω2) and the intensities of hypersensitive level (4G5/2) is in good coincidence following the Judd-Ofelt theory. 相似文献