全文获取类型
收费全文 | 158篇 |
免费 | 13篇 |
国内免费 | 8篇 |
专业分类
化学 | 29篇 |
晶体学 | 6篇 |
力学 | 77篇 |
综合类 | 2篇 |
数学 | 20篇 |
物理学 | 45篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 15篇 |
2012年 | 5篇 |
2011年 | 16篇 |
2010年 | 15篇 |
2009年 | 7篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2006年 | 8篇 |
2005年 | 13篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 1篇 |
1988年 | 2篇 |
1986年 | 1篇 |
排序方式: 共有179条查询结果,搜索用时 31 毫秒
111.
目的 分析胸腰椎骨折后路复位短节段内固定经椎弓根Wright 液态人工骨植骨的疗效。方法 38 例胸腰椎骨折患者结合患者的经济能力分为两组,A(未植骨)组24 例单纯行后路切复椎弓根螺钉内固定术,B(植骨)组14 例一期行后路切复椎弓根螺钉内固定并经椎弓根行椎体内Wright 液态人工骨植骨术,分别随访10~27 个月,比较两组患者拆钉时伤椎前缘高度的再压缩率、Cobb角变化及伤椎影像学的变化。结果 B 组患者拆钉时伤椎前缘高度再压缩率为(5.43±2.71)%,术后Cobb 角增大为(2.03±0.51)°,与A 组(6.29±2.24)°相比差异有统计学意义(P<0.05),A 组患者术后不同程度的出现蛋壳样改变,其中2例出现断钉,1例患者出现上位椎弓根钉切割出椎体,而B 组患者未出现明显蛋壳样改变及断钉现象。结论 胸腰椎骨折后路复位短节段椎弓根钉内固定经椎弓根Wright 液态人工骨植骨能明显改善伤椎骨折的愈合,维持椎体的高度,减少蛋壳样改变及断钉等情况的发生。 相似文献
112.
113.
114.
115.
高温高压花岗岩钻孔实验表明,温度低于500℃,静水应力低于150MPa 状态下,岩体的钻孔变形均属于稳态蠕变变形阶段. 该文选取了广义开尔文模型来反映其特征,通过拉普拉斯变换及逆变换,详细推演出了钻孔径向位移解析解,并且考虑温度-应力的耦合效应,给出了模型参数随温度及应力变化的关系式. 利用该关系进行拟合计算,说明广义开尔文模型来表达高温高压环境中的花岗岩稳态蠕变变形特性,寻求蠕变参数是合理可靠的. 该文对于高温岩体地热资源开发中的钻孔施工与维护、钻孔变形量预测等方面,具有实际的指导意义. 相似文献
116.
A plastic crack model for smectic A liquid crystals under longitudinal shear is suggested. The solution of the screw dislocation in smectic A is the key to the correct result that we obtained by overcoming a longstanding puzzle. We further use the dislocation pile-up principle and the singular integral equation method to construct the solution of the crack in the phase. From the solution, we can determine the size of the plastic zone at the crack tip and the crack tip opening (tearing) displacement, which are the parameters relevant to the local stability/instability of materials. Our results may be useful for developing soft-matter mechanics. 相似文献
117.
118.
Wensong Yang Shu Li Zhonghua Li Jun Sun 《Acta Mechanica Solida Sinica》2007,20(4):369-373
A plastic deformation zone near a screw dislocation is treated as an equivalent trans- formation inclusion by means of the Eshelby inclusion theory.A closed-form solution for deter- mining the interaction between a screw dislocation and a plastically deformed zone of an arbitrary shape is obtained by using the solution between a dislocation and an equivalent transformation inclusion. 相似文献
119.
Liu Yanzhu 《Acta Mechanica Sinica》1988,4(2):165-174
In the present paper the concept of screw in classical mechanics is expressed in matrix form, in order to formulate the dynamical
equations of the multibody systems. The mentioned method can retain the advantages of the screw theory and avoid the shortcomings
of the dual number notation. Combining the screw-matrix method with the tool of graph theory in Roberson/Wittenberg formalism.
We can expand the application of the screw theory to the general case of multibody systems. For a tree system, the dynamical
equations for eachj-th subsystem, composed of all the outboard bodies connected byj-th joint can be formulated without the constraint reaction forces in the joints. For a nontree system, the dynamical equations
of subsystems and the kinematical consistency conditions of the joints can be derived using the loop matrix. The whole process
of calculation is unified in matrix form. A three-segment manipulator is discussed as an example.
This work is supported by the National Natural Science Fund. 相似文献
120.
A photopolymer based on N-(phenyl)maleimide was synthesized and the liquid crystal (LC) alignment effects of the photopolymer layer on homeotropic alignment were studied. Good LC alignment with UV exposure of PMI5CA (N-(phenyl)maleimide with a 5-carbon chain cinnamoyl group) was obtained. However, defective LC alignment was observed for PMI3CA (N-(phenyl)maleimide with a 3-carbon chain cinnamoyl group) and PMIF (N-(phenyl)maleimide including a fluoro-cinnamoyl group). Good LC alignment with UV exposure on the PMI5CA surface was observed with annealing temperature up to 150°C. It seems that the LC aligning ability of the photopolymer layers based on N-(phenyl)maleimide depends on the side chain length of the photopolymer. 相似文献