全文获取类型
收费全文 | 353篇 |
免费 | 13篇 |
国内免费 | 11篇 |
专业分类
化学 | 68篇 |
力学 | 60篇 |
数学 | 156篇 |
物理学 | 93篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 19篇 |
2013年 | 29篇 |
2012年 | 21篇 |
2011年 | 27篇 |
2010年 | 32篇 |
2009年 | 35篇 |
2008年 | 22篇 |
2007年 | 24篇 |
2006年 | 18篇 |
2005年 | 19篇 |
2004年 | 13篇 |
2003年 | 14篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有377条查询结果,搜索用时 375 毫秒
101.
102.
�����������۵ĵ����������������о� 总被引:1,自引:0,他引:1
介绍了自行研制的直流非转移弧等离子体炬的结构和工作原理。运用相似理论,研究了该等离子体炬的电热特性与运行参数,比如气体流量、弧功率的关系,并将计算值与实验结果进行了比较。结果表明,计算值与实验结果吻合较好,可以利用获得的公式来对炬进行结构改进和参数优化。 相似文献
103.
Justyna Sikorska 《Journal of Mathematical Analysis and Applications》2005,311(1):209-217
We study the stability problem for mappings satisfying the equation
‖f(x−y)‖=‖f(x)−f(y)‖. 相似文献
104.
C.Y. Wang 《International Journal of Non》2008,43(5):377-382
The stagnation flow towards a shrinking sheet is studied. A similarity transform reduces the Navier-Stokes equations to a set of non-linear ordinary differential equations which are then integrated numerically. Both two-dimensional and axisymmetric stagnation flows are considered. It is found that solutions do not exist for larger shrinking rates and may be non-unique in the two-dimensional case. The non-alignment of the stagnation flow and the shrinking sheet complicates the flow structure. Convective heat transfer decreases with the shrinking rate due to an increase in boundary layer thickness. 相似文献
105.
茵陈挥发油GC-MS指纹图谱分析 总被引:9,自引:0,他引:9
建立了茵陈挥发油GC-MS指纹图谱,将正交投影算法用于不同样本中共有峰的提取,提高了共有峰的识别能力,降低了由于保留时间的漂移、质谱检索匹配度不高以及色谱峰重叠而引起的共有峰识别的难度.采用共有峰率、变异率及相似度等几个指标对4个不同产地的茵陈挥发油成分进行了评价,从共性、差异和整体性等多个方面全面表征茵陈挥发油的化学模式特征.结果表明,不同产地的茵陈挥发油成分大致相同,该指纹图谱可用于茵陈中挥发油成分的质量控制. 相似文献
106.
Zhenya Yan 《Journal of Mathematical Analysis and Applications》2011,380(2):689-4279
We report the analytical one- and two-rogon-like solutions for the two-dimensional nonlocal nonlinear Schrödinger equation by means of the similarity transformation. These obtained solutions can be used to describe the possible physical mechanisms for rogue-like wave phenomenon. Moreover, the free function of space y involved in the obtained solutions excites the abundant structures of rogue-like wave propagations. The Hermite-Gaussian function of space y (normalized function) is, in particular, chosen to depict the dynamical behaviors for rogue-like wave phenomenon. 相似文献
107.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(9):3086-3097
In this paper, we investigate the flow, heat and mass transfer of a viscous fluid flow over a stretching sheet by including the blowing effects of mass transfer under high flux conditions. Mass transfer in this work means species transfer and is different from mass transpiration for permeable walls. The new contribution from this work is, for the first time, to consider the coupled blowing effects from massive species transfer on flow, heat, and species transfer for a stretching plate. Based on the exact solutions of the momentum equations, which are valid for the whole Navier–Stokes equations, the energy and mass transfer equations are solved exactly and the effects of the blowing parameter, the Schmidt number, and the Prandtl number on the flow, heat and mass transfer are presented and discussed. The solution is given in terms of an incomplete Gamma function. It is found the coupled blowing effects due to mass transfer can have significant influences on velocity profiles, drag, heat flux, as well as temperature and concentration profiles. These solutions provide rare results with closed form analytical expressions and can be used as benchmark problem for numerical code validation. 相似文献
108.
We present a new axiomatization of logic for dependencies in data with grades, which includes ordinal data and data over domains with similarity relations, and an efficient reasoning method that is based on the axiomatization. The logic has its ordinary-style completeness characterizing the ordinary, bivalent entailment as well as the graded-style completeness characterizing the general, possibly intermediate degrees of entailment. A core of the method is a new inference rule, called the rule of simplification, from which we derive convenient equivalences that allow us to simplify sets of dependencies while retaining semantic closure. The method makes it possible to compute a closure of a given collection of attributes with respect to a collection of dependencies, decide whether a given dependency is entailed by a given collection of dependencies, and more generally, compute the degree to which the dependency is entailed by a collection of dependencies. We also present an experimental evaluation of the presented method. 相似文献
109.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(9):2928-2934
We investigate the presence of localized analytical solutions of the Schrödinger equation with logarithm nonlinearity. After including inhomogeneities in the linear and nonlinear coefficients, we use similarity transformation to convert the nonautonomous nonlinear equation into an autonomous one, which we solve analytically. In particular, we study stability of the analytical solutions numerically. 相似文献
110.
When a nonhomogeneous solid is melting from below, convection may be induced in a thermally–unstable melt layer. In this study,
the onset of buoyancy-driven convection during time-dependent melting is investigated by using similarly transformed disturbance
equations. The critical Darcy–Rayleigh numbers based on the melt-layer thickness, Ra
H,c, are found numerically for various conditions. For small superheats, the present predictions show that Ra
H,c is located between 27.1 and 4π
2 and it approaches the well-known results of the original Horton–Rogers–Lapwood problem. However, for high superheats, it
is dependent on the phase change rate λ and the relation of Ra
H,c λ = 25.89 is shown. 相似文献