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321.
322.
FANG Jin-Qing BI Qiao LI Yong LU Xin-Biao LIU Qiang 《理论物理通讯》2007,48(2):377-383
Small worm effects in the harmonious unifying hybrid preferential model (HUHPM) networks are studied both numerically and analytically. The idea and method of the HUHPM is applied to three typical examples of unweighted BA model, weighted BBV model, and the TDE rnodel, so-called HUHPM-BA, HUHPM-BBV and HUHPM- TDE networks. Comparing the HUHPM with current typical models above, it is found that the HUHPM networks has the smallest average path length and the biggest average clustering coefficient. The results demonstrate that the HUHPM is more suitable not only for the un-iveighted models but also for the weighted models. 相似文献
323.
Here, we review the recent progress in the characterisation and utilisation of coacervates as protocell models in the origin of life studies. We provide evidence that coacervation could have played a unique role during the origin of life, based on its ability to form from a range of different prebiotically relevant molecules; partition solutes; support and alter RNA catalysis and readily deform its shape. We discuss how these properties could have been important for the formation of the first membrane-bound cells, supporting RNA-peptide evolution and primitive metabolism, and in replicating and proliferating by growth and division processes. 相似文献
324.
Based on the model of the same degree of all nodes we proposed
before, a new algorithm, the so-called “spread all over vertices” (SAV) algorithm, is proposed for generating small-world properties from a regular ring lattices. During randomly rewiring connections the SAV is used to keep the unchanged number of links. Comparing the SAV algorithm with the Watts-Strogatz model and the “spread all over boundaries” algorithm, three methods can have the same topological properties of the small world networks. These results offer diverse formation of small world networks. It is helpful to the research of some applications for dynamics of mutual oscillator inside
nodes and interacting automata associated with networks. 相似文献
325.
We give further theoretical consideration to the solution of flow problems involving abrupt changes in geometry using implicit rheological equations of state, so that the stress components are dependent variables along with the velocity components and the pressure.Attention is confined to the expansion/contraction/expansion problems and main interest centres on the effect of long range memory on flow characteristics, particularly the recirculating vortices arising from the presence of the abrupt changes in geometry. 相似文献
326.
327.
Misao Sasaki 《Pramana》2004,63(4):785-796
There has been substantial progress in brane-world cosmology in recent years. Much attention has been particularly paid to the second Randall-Sundrum (RS2) scenario in which a single positive-tension brane is embedded in a five-dimensional space-time, called the bulk, with a negative cosmological constant. This brane-world scenario is quite attractive because of the non-trivial geometry in the bulk and because it successfully gives four-dimensional general relativity in the low energy limit. After reviewing basic features of the RS2 scenario, we consider a brane-world inflation model driven by the dynamics of a scalar field living in the five-dimensional bulk, the so-called bulk inflaton model. An intriguing feature of this model is that the projection of the bulk inflaton on the brane behaves just like an ordinary inflaton in four dimensions in the low energy regime,H 2 l 2 « 1, whereH is the Hubble expansion rate of the brane andl is the curvature radius of the bulk. We then discuss the cosmological perturbation on superhorizon scales in this model. We find that, even under the presence of spatial inhomogeneities, the model is indistinguishable from the standard four-dimensional inflation toO(H 2 l 2). That is, the difference may appear only atO(H 14 l 4). 相似文献
328.
Emanuel Gallo 《General Relativity and Gravitation》2004,36(6):1463-1471
In this article we extend to higher dimensional space-times a recent theorem proved by Salgado which characterizes a three-parameter family of static and spherically symmetric solutions to the Einstein Field Equations. As it happens in four dimensions, it is shown that the Schwarzschild, Reissner-Nordström and global monopole solutions in higher dimensions are particular cases from this family. 相似文献
329.
基于六所部属师范大学数学专业免费师范生现状的调查数据,探讨是否允许考研和学习动力之间的关系.经典累积logistic模型对数据的拟合不佳.利用累积logistic混合模型,很好的拟合了数据,得到如果允许考研将提升免费师范生学习积极性的结论. 相似文献
330.
研究了新试剂2-〔2'-(6'-甲磺酰-苯并噻唑)偶氮〕-5-二甲氨基苯甲酸(MSBTAMB)与铜(Ⅱ)的显色反应。试验表明,在pH2.0~5.1和40%乙醇介质中,Cu(Ⅱ)与MSBTAMB形成1+1稳定的配合物,其最大吸收波长为642nm,用单波长法测得配合物的Σ(642)=6.74×104·mol-1·cm-1,双波长法测得的Σ(642,546)=1.09×105L·mol-1·cm-1。铜量在0~0.72μg/mL范围内合符比尔定律。制定的方法用于人发和纯铝中微量铜的测定,结果满意。 相似文献