全文获取类型
收费全文 | 563篇 |
免费 | 37篇 |
国内免费 | 34篇 |
专业分类
化学 | 72篇 |
晶体学 | 2篇 |
力学 | 218篇 |
综合类 | 1篇 |
数学 | 58篇 |
物理学 | 283篇 |
出版年
2024年 | 3篇 |
2023年 | 2篇 |
2022年 | 13篇 |
2021年 | 9篇 |
2020年 | 17篇 |
2019年 | 10篇 |
2018年 | 13篇 |
2017年 | 28篇 |
2016年 | 25篇 |
2015年 | 17篇 |
2014年 | 54篇 |
2013年 | 25篇 |
2012年 | 22篇 |
2011年 | 41篇 |
2010年 | 32篇 |
2009年 | 40篇 |
2008年 | 39篇 |
2007年 | 38篇 |
2006年 | 28篇 |
2005年 | 18篇 |
2004年 | 28篇 |
2003年 | 22篇 |
2002年 | 19篇 |
2001年 | 21篇 |
2000年 | 8篇 |
1999年 | 12篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有634条查询结果,搜索用时 31 毫秒
51.
This paper deals with the numerical implementation of the exact boundary controllability of the Reissner model for shallow spherical shells (Ref. 1). The problem is attacked by the Hilbert uniqueness method (HUM, Refs. 2–4), and we propose a semidiscrete method for the numerical approximation of the minimization problem associated to the exact controllability problem. The numerical results compare well with the results obtained by a finite difference and conjugate gradient method in Ref. 5.This work was done when the first two authors were at CNR-IAC, Rome, Italy as Graduate Students. 相似文献
52.
Vibration isolation plays an important role in both the vibration and noise control of building services equipment. To evaluate vibration isolation performance, the force transmissibility method is commonly adopted. However, increasing the damping effect in the force transmissibility method reduces both the resonance peak value and the isolation performance in the “isolation region”. The limitation of the method is that the transmitted displacement of a floor structure and the interaction of mounting points are neglected. To include the floor displacement and the interaction of mounting points, Mak and Su recently proposed the power transmissibility method to assess the performance of vibration isolation. In this paper, the effect of viscous damping on power transmissibility is investigated. A practical procedure for experimentally determining the damping ratio is also given. 相似文献
53.
The effect of dynamical self-orientation and its applicability for the identification of natural frequencies of the investigated
systems is demonstrated in this paper. Unidirectional vibration exciter is fixed to the investigated systems via a pivot link
and can rotate around it. It is shown that the exciter changes its orientation in the steady state motion mode when the frequency
of excitation sweeps over the fundamental frequency of the examined system. Approximate analytical analysis of the discrete
system illustrates the basic principle of the effect of dynamical self-orientation. Numerical analysis of both the discrete
and different continuous elastic systems confirms the applicability of the effect of self-orientation for the identification
of natural frequencies. 相似文献
54.
C. Chevennement-Roux T. Dreher P. Alliot E. Aubry J.-P. Lainé L. Jézéquel 《Experimental Mechanics》2007,47(2):201-210
The optimization of wiper systems under various conditions and the creation of a product which is as robust as possible are
the main objectives for an equipment supplier. However, in certain conditions, instabilities can appear and generate wiping
defects due to the rubber-glass contact. To improve wiping quality and to reduce the number of test stages for design, this
study proposes a wiper system modeling method. The wiper system is represented by a rigid blade holder on which a rubber blade
is fitted. This rigid blade system is used on a flat test bench at constant wiping velocity. The model is based on modal synthesis
methods and will be validated through comparison with experimental tests under various conditions. The right correlation obtained
allows the same modelling method to be applied to the new generation of flexible wiper blades which take account of the degree
of freedom of the wiper blade flexions. So, a new computation tool will be developed and validated through experimentation
on a specific test bench. 相似文献
55.
Here, the large amplitude free flexural vibrations of isotropic/laminated orthotropic rings are investigated, using a shear flexible curved beam element based on field consistency principle. A laminated refined beam theory is introduced for developing the element, which satisfies the interface transverse shear stress and displacement continuity, and has a vanishing shear stress on the inner and outer surfaces of the beam. The formulation includes in-plane and rotary inertia effects, and the non-linearity due to the finite deformation of the ring. The governing equations obtained using Lagrange's equations of motion are solved through the direct integration technique. Amplitude-frequency relationships evaluated from the dynamic response history are examined. Detailed numerical results are presented considering various parameters such as radius-to-thickness ratio, circumferential wave number and ovality for isotropic and laminated orthotropic rings. The nature and degree of the participation of various modes in non-linear asymmetric vibration of oval ring brought out through the present study are useful for accurate modelling of the closed non-circular structures. 相似文献
56.
Isotactic polypropylene(i PP) samples obtained by pressure vibration injection molding(PVIM) and conventional injection molding(CIM) were studied by polarized-light microscopy(PLM), respectively. It was found that the alternating bright and dark banded spherulites were generated in the transitional region of PVIM parts. It is the first time that the banded spherulites of isotactic polypropylene were observed in polymer processing. What's more, the banded spherulites were proved to be constituted of ?-form crystal by hot stage polarized-light microscopy(HT-PLM) and wide angle X-ray diffraction(WAXD). Morphology of the banded spherulites was also studied by scaning electronical microscopy(SEM). 相似文献
57.
大型电力变压器线圈轴向非线性振动研究 总被引:10,自引:0,他引:10
本文对具有非线性特性的变压器线圈在稳态及短路电动力下的轴向动态响应进行了单自由度和多自由度的理论和数值研究,对提出的安匝平衡时的单自由度力学模型,分别利用多惊讶法和打靶法进行了稳态响应的解析和数值分析,并对打靶法中差商阵的求法进行了改进,减少了计算工作量,对于典型的单柱式变压器线罪状系统建立了非线性多自由度模型,进行了短路响应数值分析,得出了响应特征及其和变压器各参数之关系,同时,进行了模型变压器短路试验,进行了轴向动态响应力等一系列测量,分析结果与试验结果相符。 相似文献
58.
V.I. Yudovich S.M. Zenkovskaya V.A. Novossiadliy A.L. Shleykel 《Comptes Rendus Mecanique》2004,332(4):257-262
We consider the dynamical stability of horizontal fluid layer, performing harmonic oscillations in vertical direction. The continued fractions approach allowed us to avoid the conventional restriction to the case of small viscosity and almost-resonant frequencies. Our numerical results cover a wide range of the parameters (viscosity, amplitude and frequency of the oscillation, and depth of the layer). To cite this article: V.I. Yudovich et al., C. R. Mecanique 332 (2004). 相似文献
59.
Yao Koutsawa El Mostafa Daya 《International Journal of Solids and Structures》2007,44(25-26):8735-8750
Static behavior and free vibration analysis of laminated glass beam on viscoelastic supports are performed. For the static case, an analytical way is developed for analyzing and optimization of laminated glass beam with general restraints at the boundaries. In the case of free linear vibrations, the modal properties of the glass are determined using a finite element method which is a powerful tool in the design of support damping treatment of a sandwich glass for passive vibration control. 相似文献
60.
Dan N. Borza 《Experimental Mechanics》2002,42(4):432-438
Electronic holography is a well-established technique used in real-time, non-contact, whole-field displacement measurements.
When using the real-time, time-averaged method for vibration measurments, the quantitative interpretation of dense fringe
patterns is difficult because of speckle noise. Even when speckle-reducing procedures are used, such as multiple-frame averaging
or rotation of the illumination beam, the remaining speckles and decreasing visibility of higher-order Bessel fringes are
serious limitations. The primary objective of this paper is to present a new realtime, interferometric method for mechanical
vibration measurements and the associated quantitative interpretation. The fringe pattern obtained by this method is quasi-binary
and half as dense as in the time-averaged method. The method greatly improves the overall visibility (contrast, resolution)
of vibration fringe patterns without any sacrifice in the real-time capabilities. Quantitative fringe interpretation is straightforward
and based on binary fringe tracking. It allows quantitative measurements in situations where the time-averaged fringe processing
fails. 相似文献