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排序方式: 共有373条查询结果,搜索用时 15 毫秒
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The structure of interaction plays an important role in the outcome of evolutionary games. This study investigates the evolution of stochastic strategies of the prisoner's dilemma played on structures ranging from lattices to small world networks. Strategies and payoffs are analyzed as a function of the network characteristics of the node they are playing on. Nodes with lattice‐like neighborhoods tend to perform better than the nodes modified during the rewiring process of the construction of the small‐world network. © 2007 Wiley Periodicals, Inc. Complexity 12:22–36, 2006 相似文献
33.
It is very likely that the main driving force of enzyme evolution is the requirement to improve catalytic and regulatory efficiency which results from the intrinsic performance as well as from the spatial and functional organization of enzymes in living cells.Kinetic co-operativity may occur in simple monomeric proteins if they display “slow” conformational transitions, at the cost of catalytic efficiency. Oligomeric enzymes on the other hand can be both efficient and co-operative. We speculate that the main reason for the emergence of co-operative oligomeric enzymes is the need for catalysts that are both cooperative and efficient. As it is not useful for an enzyme to respond to a change of substrate concentration in a complex kinetic way, the emergence of symmetry has its probable origin in a requirement for “functional simplicity”.In a living cell, enzyme are associated with other macromolecules and membranes. The fine tuning of their activity may also be reached through mutations of the microenvironment. Our hypothesis is that these mutations are related to the vectorial transport of molecules, to achieve the hysteresis loops of enzyme reactions generated by the coupling of reaction and diffusion, through the co-operativity brought about by electric interactions between a charged substrate and a membrane, and last but not least, through oscillations. As the physical origins of these effects are very simple and do not require complex molecular devices, it is very likely that the functional advantage generated by the spatial and functional organization of enzyme molecules within the cell have appeared in prebiotic catalysis or very early during the primeval stages of biological evolution.We shall began this paper by presenting the nature of the probable earliest catalysts in the RNA world. 相似文献
34.
Michal Demetrian 《International Journal of Theoretical Physics》2006,45(12):2297-2304
The second order Coleman–de Luccia instanton and its action in the Randall–Sundrum type II model are investigated and the comparison with the results in Einstein’s general relativity is done in the present paper.
PACS Numbers: 98.80.Cq. 相似文献
35.
K. A. Bronnikov S. A. Kononogov V. N. Melnikov 《General Relativity and Gravitation》2006,38(7):1215-1232
We discuss possible variations of the effective gravitational constant with length scale, predicted by most of alternative theories of gravity and unified models of physical interactions. After giving a brief general exposition, we review in more detail the predicted corrections to Newton’s law of gravity in diverse brane world models. We consider various configurations in 5 dimensions (flat, de Sitter and AdS branes in Einstein and Einstein–Gauss–Bonnet theories, with and without induced gravity and possible incomplete graviton localization), 5D multi-brane systems and some models in higher dimensions. A common feature of all models considered is the existence of corrections to Newton’s law at small radii comparable with the bulk characteristic length: at such radii, gravity on the brane becomes effectively multidimensional. Many models contain superlight perturbation modes, which modify gravity at large scale and may be important for astrophysics and cosmology. 相似文献
36.
叶良驷 《宁波大学学报(理工版)》1993,(2)
以宁波大学为实例,在《大学生体育合格标准》的试行后通过对大学生心理、生理和能力等方面进行综合分析以及通过随机抽样、问卷表调查、座谈会等办法对各种数据(包括达标成绩、身体素质、形态机能、学习成绩)运用均数,标准差等统计方法进行分析处理,结果表明,实施《标准》既必要,也可行.在高校实施《大学生体育合格标准》的条件已基本具备,大学生对《标准》的各项要求是有承受能力的. 相似文献
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On the basis of modularity optimization, a genetic algorithm is proposed to detect community structure in networks by defining a local search operator. The local search operator emphasizes two features: one is that the connected nodes in a network should be located in the same community, while the other is “local selection” inspired by the mechanisms of efficient message delivery underlying the small‐world phenomenon. The results of community detection for some classic networks, such as Ucinet and Pajek networks, indicate that our algorithm achieves better community structure than other methodologies based on modularity optimization, such as the algorithms based on betweenness analysis, simulated annealing, or Tasgin and Bingol's genetic algorithm. © 2009 Wiley Periodicals, Inc. Complexity, 2010 相似文献
39.
Leonie Tickle Tim Kyng Leigh N. Wood 《International Journal of Mathematical Education in Science & Technology》2013,44(2):200-213
The role of universities in preparing students to use spreadsheet and other technical software in the financial services workplace has been investigated through surveys of university graduates, university academics, and employers. It is found that graduates are less skilled users of software than employers would like, due at least in part to a lack of structured formal training opportunities in the workplace, and a lack of targeted, coherent learning opportunities at university. The widespread and heavy use of software in the workplace means that there is significant potential for productivity gains if universities and employers address these issues. 相似文献
40.
R. Butler F. Turner† 《International Journal of Mathematical Education in Science & Technology》2013,44(1):33-49
The rate of convergence of a Fourier‐series representation of a given function depends on the nature of the function and of its derivatives. This is shown by using the graphical outputs of a desk computer for different cases. For full‐range series, the effects of continuity and discontinuity of the function and its first derivatives are shown first. The advantage of half‐range formulae due to the free choice of function in the second half‐range are demonstrated next, along with the importance of choice of sine and cosine series according to the function being represented. Finally, a method is given of modifying the given function in a simple manner whereby a dramatic increase in the rate of convergence of the Fourier series is obtained. Examples of the Gibbs overshoot and its elimination are included. 相似文献