全文获取类型
收费全文 | 188篇 |
免费 | 10篇 |
国内免费 | 9篇 |
专业分类
化学 | 58篇 |
力学 | 45篇 |
综合类 | 3篇 |
数学 | 6篇 |
物理学 | 12篇 |
综合类 | 83篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 1篇 |
2020年 | 1篇 |
2018年 | 5篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 10篇 |
2011年 | 6篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 6篇 |
2007年 | 19篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 9篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有207条查询结果,搜索用时 0 毫秒
201.
采用压汞法研究了不同固结压力作用下具有强结构性的珠海海积软土的微观孔隙入口孔径分布与应力水平的关系,通过X-射线衍射试验(XRD)对其黏土矿物含量进行定量分析,并与加拿大Regina黏土进行了对比.研究结果表明:珠海天然海积软土的孔隙入口孔径分布为主单峰分布;当应力水平小于结构屈服应力时,其孔隙入口孔径分布和微观结构与应力水平无关;当应力水平达到结构屈服应力时,大中孔隙(200 nm)的含量明显减少,而小孔隙(20~200 nm)含量则基本不变;在屈服后阶段,小孔隙含量锐减,整体孔隙空间的孔径趋于均匀.最后,初步分析了珠海海积软土和Regina黏土孔隙分布差异的原因是颗粒组成分布和黏土矿物成分的不同. 相似文献
202.
203.
借助不同温度下的固溶处理,得到一系列具有不同溶质原子浓度及析出相含量的Al-4.5wt%Cu合金材料试件.比较这些试件在拉伸实验中的锯齿形屈服现象的时空特性,分析溶质原子与析出相对位错运动的影响,从而探究动态应变时效产生的微观机理.实验结果显示,当固溶处理温度由500℃逐步降低,应力-时间曲线上的应力锯齿跌落幅值逐渐减小,并在300℃时达到最小.继续降低固溶处理温度至100℃,应力锯齿跌落幅值又逐渐增大.同时,热处理方式的改变对剪切带的传播特性也有显著影响.实验发现,固溶处理温度高于300℃时,溶质原子对DSA的影响强于析出相;反之,固溶处理温度低于300℃时,析出相对DSA的影响强于溶质原子;室温下析出相是影响Al-4.5wt%Cu合金DSA机理的主要因素.
关键词:
铝铜合金
锯齿形屈服
动态应变时效
固溶处理 相似文献
204.
205.
The principal features of the volumetric as well as the viscoelastic response of mechanically stimulated glasses can be summarized as follows: i) the time-aging time shift factors contract upon increasing the probe stress (i.e. the stress apparently modifies the volume recovery kinetics), ii) the volume recovery baseline remains unaltered (i.e. the underlying structure of the stimulated glass remains unchanged) iii) yielding scales linearly with the logarithmic of the strain rate. Here we present a review of the above features with aid of a series of numerically simulated results concerning the responses of glassy polycarbonate. Simulations are obtained coupling a modified KAHR equation with the constitutive law for linear viscoelasticity within the domain of the reduced time. It will be shown that by using a minimum of experimental (PVT and linear viscoelastic) data inputs even the subtle intricacies can be predicted. Furthermore a new class of results concerning the stress-strain behaviour of glassy polymers is presented that never appeared before. 相似文献
206.
The tensile deformation behaviour of poly(1-butene) and two of its ethylene copoloymers was studied at room temperature. This was done by investigating true stress-strain curves at constant strain rates, elastic recovery and stress relaxation properties and in-situ WAXS patterns during the deformation process. As for a series of semicrystalline polymers in previous studies, a strain-controlled deformation behaviour was found. The differential compliance, the recovery properties and the stress relaxation curves changed simultaneously at well-defined points. The strains at which these points occurred along the true stress-strain remained constant for the different samples despite their different percentage crystallinities. The well-defined way in which the different samples respond to external stresses complies with the granular substructure of the crystalline lamellae in a semicrystalline polymer. 相似文献
207.
The correlation between the morphology and the deformation mechanism in styrene/butadiene block copolymers having modified architecture and in blends with homopolymer polystyrene (hPS) was studied. It was demonstrated that the morphology formation in the block copolymers is highly coupled with their molecular architecture. In particular, the micromechanical behaviour of a star block copolymer and its blends with polystyrene was investigated by using electron microscopy and tensile testing. A homogeneous plastic flow of polystyrene lamellae (thin layer yielding) was observed if the lamella thickness was in the range of 20 nm. The deformation micromechanism switched to the formation of craze-like deformation zones when the average PS lamella thickness changed to about 30 nm and more. 相似文献