全文获取类型
收费全文 | 174篇 |
免费 | 25篇 |
国内免费 | 21篇 |
专业分类
化学 | 95篇 |
晶体学 | 2篇 |
力学 | 2篇 |
数学 | 38篇 |
物理学 | 83篇 |
出版年
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 11篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 29篇 |
2012年 | 7篇 |
2011年 | 9篇 |
2010年 | 6篇 |
2009年 | 9篇 |
2008年 | 10篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 7篇 |
2003年 | 9篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1976年 | 1篇 |
1948年 | 3篇 |
排序方式: 共有220条查询结果,搜索用时 15 毫秒
121.
以水溶性聚合物为保护剂,采用化学还原法制备了银纳米粒子,分别利用透射电子显微镜、紫外可见光谱、同步光散射光谱等手段对其进行了表征,并探索了制备银纳米粒子的最佳实验条件。通过将银纳米粒子-聚合物溶液进行脱水,得到含有银纳米粒子的固态聚合物膜。将固态聚合物膜重新溶解于水,其水溶液的紫外可见光谱与脱水前的溶液进行了比较,发现两者性质并无明显差异。因此,将银纳米粒子分散固定在聚合物膜中是一种崭新而有效的银纳米粒子制备和存储方法。 相似文献
122.
We take advantage of recent (see Graf et al., 2008; Pages and Wilbertz, 2012) and new results on optimal quantization theory to improve the quadratic optimal quantization error bounds for backward stochastic differential equations (BSDE) and nonlinear filtering problems. For both problems, a first improvement relies on a Pythagoras like Theorem for quantized conditional expectation. While allowing for some locally Lipschitz continuous conditional densities in nonlinear filtering, the analysis of the error brings into play a new robustness result about optimal quantizers, the so-called distortion mismatch property: the -mean quantization error induced by -optimal quantizers of size converges at the same rate for every . 相似文献
123.
Data were obtained for the solution behaviour of cadmium(II) and mercury(II) carboxylates in alcohols. A brief survey of the arguments about the existence of micelles and the current models of surfactant aggregation in non-aqueous media is presented. The plots of solubility against the carboxylate or alcohol chain length are linear for both cadmium and mercury soaps with the solubility having values higher in secondary than primary alcohols. The solution behaviour of metal 9, 10-dihydroxyoctadecanoates shows the effect on solubility, of substitution of dihydroxyl groups at the middle of the carbon chain. Recrystallisation temperatures of the dihydroxyoctadecanoates suggest the loss of stereochemical configuration in solution and indicate similarity in the mode of aggregation. The solution temperatures of cadmium soaps are very close to the temperatures of their phase transitions while those of mercury and lead soaps are lower than their fusion or phase transition temperatures. This behaviour is interpreted to be due to differences in the energy required for the disruption of the crystal structure which dominates the solubility mechanism. 相似文献
124.
The Incomplete-Fusion-nagmentation Model has been used to reproduce nicely the experimental evidence of liquid-gas phase transition probed in the reaction of Au + Au at 600A MeV. The analysis of the relative yields of decay modes for the projectile remnant as a function of bound> shows clearly the competition and transformation processes of various decay modes of projectile remnant with decreasing of bound>. The agreement between theoretical and experimental results for the anaJysis of relative yield of decay modes indicates that the experimental evidence of liquid-gas phase transition is composed of the decay mode transformations. 相似文献
125.
LI Wen-Xin SUN Tong-Yu QI Da-Hai SUN Ru-Lin SA Ben-Hao WU Ding-Qing ZHAO Li-Li JIN Gen-Ming 《中国物理C(英文版)》1990,14(8):745-752
Cross sections and average forward ranges were determined for 35 target residues from the interaction of copper with 44MeV/A12C ions with nuclear chemistry techniques.From these data the isobaric yield distribution,the mass yield distribution and the longitudinal momentum transfer were obtained.The mass yield distribution and the isobaric yield distribution are in good agreement with those calculated from a modified statistical model and corresponding Monte Carlo technique. 相似文献
126.
we have identified the first-order mixing amplitude of πNN process described by the hadron model with the second-order mixing amplitude of the same process described by the quark model.Then the expression for the coupling constant fπ of the πNN vertex with different quark wave functions and gluon propagators in different approximations has been derived. The calculation results of fπ have been compared with experimental data. 相似文献
127.
LUCIAE, a hadronic and string cascade model and its corresponding event generator are used to analyse strangeness production singly and multiply in p-Pb and Pb-Pb collisions at 158 A GeV. Spectra of multiplicity and transverse mass for single (Λ, Λ) and multiple (Ξ-, Ξ-, Ω-, Ω-) strangeness are given. In LUCIAE model it suggests a physical mechanism, i.e. the dependence of the strange quark suppression factor on incident energy, projectile mass and centrality of colliding system might result in increase of yield of strange particles with increasing the above three parameters. Calculations from the model reconstruct well the WA97 experimental data: increase of yield of strange particles with increasing centrality and increase of strangeness enhancement with increasing number of strange quarks, in relativistic nucleus-nucleus collisions. 相似文献
128.
Asymptotic analysis of the problem describing deformation ofa thin cylindrical plate with clamped lateral side is performed.The problem is considered under the most general statement withthe plate being laminated and consisting of an arbitrary numberof nonhomogeneous and anisotropic (21 elastic moduli) layers.Explicit integral representations of the differential operatorswhich form the two-dimensional model of the plate are derived.In the case when the elastic moduli of each of the layers areconstant, these integral representations turn into algebraicones. The asymptotic procedure is justified with the help ofa weighted inequality of Korn's type. The error estimates obtainedgive a rigorous mathematical proof of both of Kirchhoff's hypotheses(kinematic and static) and shed light on the well-known intrinsicinconsistency of two of the hypotheses. 相似文献
129.
130.