全文获取类型
收费全文 | 270篇 |
免费 | 20篇 |
国内免费 | 31篇 |
专业分类
化学 | 189篇 |
晶体学 | 2篇 |
力学 | 48篇 |
综合类 | 4篇 |
数学 | 22篇 |
物理学 | 56篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 15篇 |
2019年 | 9篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 11篇 |
2014年 | 17篇 |
2013年 | 11篇 |
2012年 | 10篇 |
2011年 | 18篇 |
2010年 | 12篇 |
2009年 | 15篇 |
2008年 | 15篇 |
2007年 | 12篇 |
2006年 | 16篇 |
2005年 | 18篇 |
2004年 | 7篇 |
2003年 | 1篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 12篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 13篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有321条查询结果,搜索用时 31 毫秒
1.
Measurement of the First Hyperpolarizability of Substituted Ketene N,S-acetals by Hyper-Rayleigh Scattering in Solution 总被引:1,自引:1,他引:0
MeasurementoftheFirstHyperpolarizabilityofSubstitutedKeteneN,S-acetalsbyHyper-RayleighScatteringinSolutionGAOXingyu;CHENJingb... 相似文献
2.
3.
The non-isothermal crystallization kinetics of poly(ethylene terephthalate) (PET) modified by poly (ethlene glycol) (PEG) were determined by DSC. The dual linear regression method was used to evaluate the relationship between the reciprocal of t 1/2 ( the half life of crystallization) and the appropriate temperature variable. The parameters such as the activation energy (Ed) for transport, the equilibrium melting temperature (T_m~0),the nucleation parameter (ψ),themaximum crystallization temperature (T_(e, max)), and the kinetic crystallizability (G) for the copolyesters were obtained. The influence of the PEG content in PET chains on the parameters characterizing crystallization kinetics and crystallization thermodynamics was discussed. 相似文献
4.
5.
6.
本文用自制的单一或复合的微生物传感器作检测器,与高效液相色谱结合,对7种氮基酸,5种有机醇,以及同化糖与醇,维生素等7种混合体系进行分离硷测,取得较好的结果。 相似文献
7.
A sensitive and selective method using liquid chromatography with electrospray ionization mass spectrometric detection was
developed for the quantification of bilobalide and ginkgolides in canine plasma. The analytes were extracted with diethyl
ether-dichloromethane-isopropanol (6:3:1, v/v) after spiking the samples with daidzein (internal standard). The lower limit
of quantification (LLOQ) of the method was 2.5 μg L−1 for ginkgolide B and 10.0 μg L−1 for bilabolide, ginkgolide A and ginkgolide C. The accuracy of the method was within 15% of the actual values over a wide
range of plasma concentrations. The intra-day and inter-day precision was better than 15% (R.S.D.). Finally, the LC-ESI-MS
method was successfully applied to study the pharmacokinetics of ginkgolides and bilabolide after administration of Ginkgo biloba extracts to dogs. 相似文献
8.
A rigorous and practical methodology for evaluating thermal-equilibrium density matrices, finite-temperature time-dependent expectation values, and time-correlation functions is described. The method involves an extension of the matching-pursuit/split-operator-Fourier-transform method to the solution of the Bloch equation via imaginary-time propagation of the density matrix and the evaluation of Heisenberg time-evolution operators through real-time propagation in dynamically adaptive coherent-state representations. 相似文献
9.
The nonadiabatic surface hopping Herman-Kluk (HK) semiclassical initial value representation (SC-IVR) method for nonadiabatic problems is reformulated. The method has the same spirit as Tully's surface hopping technique [J. Chem. Phys. 93, 1061 (1990)] and almost keeps the same structure as the original single-surface HK SC-IVR method except that trajectories can hop to other surfaces according to the hopping probabilities and phases, which can be easily integrated along the paths. The method is based on a rather general nonadiabatic semiclassical surface hopping theory developed by Herman [J. Chem. Phys. 103, 8081 (1995)], which has been shown to be accurate to the first order in h and through all the orders of the nonadiabatic coupling amplitude. Our simulation studies on the three model systems suggested by Tully demonstrate that this method is practical and capable of describing nonadiabatic quantum dynamics for various coupling situations in very good agreement with benchmark calculations. 相似文献
10.
营养素能有效防治亚临床铅中毒,阐述了钙、铁、锌、硒及维生素等营养素与铅毒性作用的相互关系。 相似文献