全文获取类型
收费全文 | 114篇 |
免费 | 9篇 |
国内免费 | 26篇 |
专业分类
化学 | 71篇 |
力学 | 3篇 |
综合类 | 1篇 |
数学 | 10篇 |
物理学 | 64篇 |
出版年
2022年 | 4篇 |
2020年 | 4篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 10篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 11篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1992年 | 2篇 |
1986年 | 4篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有149条查询结果,搜索用时 15 毫秒
91.
An exact expression for calculating the in-medium △ absorption cross section is obtained within the framework of the self-consistent relativistic BUU approach. The medium effects on the △N→NN cross section is investigated, and it is found that the effective cross sation is suppressed in the medium near the threshold energy. The results are in a good agreement with the most recent experimental data of the TAPS collaboration. 相似文献
92.
Nearest Neighbour Level Spacing and Level Curvature Distributions of Single-Particle in Heavy Nuclei 下载免费PDF全文
The underlying Hamiltonian involved with the rotating two-center shell model is multi-parameter dependent and belongs to the Gaussian unitry ensemble(GUE).It is found that the spacing distribution and two curvature distributions(with respect to the separation and the cranked frequency,respectively)of the levels individually approach to those of GUE in the different regions of separation and cranked frequency.They,however,share a common parameter region.It is suggested that the chaotic motion of the single-particle in a heavy nucleus is possibly realized in the condition of superdeformation and high spin. 相似文献
93.
The explicit expressions for in-medium NN→N△ cross section are derived within the relativistic Boltzmann-Uehling-Uhlenbeck approach,which are given simultalleously with the other integrants of transport model such as the mean field, NN elastic scattering cross section as well as the transport equation itself based on the effective Lagrangian.Our results can reproduce the experimental data of free inelastic cross section nicely.The in-medium inelastic cross section is calculated up to twice nuclear matter density and is in agreement with the Dirac-Brueckner calculations. 相似文献
94.
1988年Pavlopoulos等人发现1,3,5,7-四甲基吡咯亚甲基BF2化合物是一个性能优良的激光染料[1].它的荧光量子效率高,激光效率比香豆素540A高10%,并具有低的三重态吸收和高的光化学稳定性.因此,在染料激光、生物荧光探针、光动力疗法等方面都有潜在的应用背景[2~4]. 相似文献
95.
We demonstrate the synthesis of monodisperse, heterostructured Pt-Ru nanocrystals with a novel core-shell structure by a one-step method. The Pt-Ru nanocrystals show excellent electrocatalytic activity towards formic acid oxidation. Such core-shell structured Pt-Ru nanocrystals are potential candidates as anode catalysts in fuel cells. 相似文献
96.
通过无电沉积/化学镀的方法分别制得石墨烯(Graphene)、 镍网(Ni foam, NF)、 钛网(Ti mesh, TM)、 碳布(Carbon cloth, CC)负载的硼化镍材料. 其中在石墨烯基底上生长的硼化镍层由规则的纳米颗粒构成, 且均匀致密. 对几种材料在碱性条件下(1.0 mol/L KOH电解质中)的水氧化电催化性能进行了研究, 结果表明, 石墨烯基底上生长的硼化镍材料(NiBx/graphene)具有最佳的水氧化电催化性能. 电流密度达到10 mA/cm2时的过电位仅为277 mV, 相应的Tafel斜率为57 mV/dec. 对石墨烯负载的硼化镍材料进行烧结, 测得过电位为330 mV, 与未烧结的样品相比电催化活性下降. 该方法所制的石墨烯负载的硼化镍材料兼具高电催化活性和稳定性, 为低成本、 高效率的水氧化非贵金属电催化剂的制备提供了新思路. 相似文献
97.
给出系统(E1),(E2)和(E3)等非线性微分系统存在闭轨的一些新的判定条件,推广了非线性微分系统极限环的存在性和唯一性许多这方面研究的结果,并大大改进了它们的某些条件.在这个基础上,还给出了系统(E1)和(E2)恰有一个极限环的一组充分条件. 相似文献
98.
1IntroductionConsideraninitial-boundaryproblellll']oftileforulBylreansoftheforwardilltime-forwal'dillspacefillitedifferellcel-lletllodforcalculatillganapproximatesolutiollIL(nh,jk)=ALeofthisproblelll,weareledtotilefollowingdifferenceschemeoftheformwilerss=k/h.Suchallequationisaparticularcaseoftilefollowillggelleralpartialdifl'erellcewhere{hij},{oil}and{fti}arerealdollblesequellcesdefilledfori,j20.Itisclearthatiftilearegiven,thenwecancalculate'I[lo;till,liZ,o;u129'u21,'u3o;''successivelyill… 相似文献
99.
The nonlinear optical properties of a new organic material, N-vinylcarbazole tricarbonyl chromium, are reported. The large two-photon absorption (TPA) coefficient and nonlinear refraction index are measured by an open-aperture Z-scan technique and closed-aperture Z-scan technique, respectively. The sample solution shows excellent optical limiting response. 相似文献
100.
Wu Xizhen LI Zhuxia ZHANG Yingxun FENG Renfa ZHUO Yizhong GU Jianzhong 《中国科学A辑(英文版)》2001,44(7):923-931
Some aspects of quantum chaos in a finite system have been studied based on the analysis of statistical behavior of quantum
spectra in nuclei. The experiment data show the transition from order to chaos with increasing excitation energy in spherical
nuclei. The dependence of the order to chaos transition on nuclear deformation and nuclear rotating is described. The influence
of pairing effect on the order to chaos transition is also discussed. Some important experiment phenomena in nuclear physics
have been understood from the point of view of the interplay between order and chaos. 相似文献