全文获取类型
收费全文 | 126篇 |
免费 | 10篇 |
国内免费 | 9篇 |
专业分类
化学 | 44篇 |
晶体学 | 3篇 |
力学 | 8篇 |
综合类 | 2篇 |
数学 | 57篇 |
物理学 | 31篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 13篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 3篇 |
2012年 | 6篇 |
2011年 | 14篇 |
2010年 | 12篇 |
2009年 | 21篇 |
2008年 | 7篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
排序方式: 共有145条查询结果,搜索用时 15 毫秒
31.
32.
本文通过Leray-Schauder度,给出Heisenberg群上四阶非线性次椭圆方程特征值问题的正解的一些存在性结果. 相似文献
33.
对国产7502B型ICP光电直读光谱光谱仪的计算机控制系统的软硬件结构及其基本运行原理进行了分析,叙述了将其原有主控制计算机从长城0520CH-Ⅱ型微机升级为IBMPC兼容奔腾机所存在的软件,硬件方面的问题及其解决办法。 相似文献
34.
张吉惠 《新疆大学学报(理工版)》1989,(2)
设 X 为自反 Banach 空间,K■X 为闭凸集,A:X→2x~* 是一个集值映象,对f∈X~* ,本文讨论变分不等式:u∈K 〈Au,v-u〉≥〈f,v-u〉Vv∈K.作为应用,在单值的情形,我们获得了关于伪收缩映象的不动点定理. 相似文献
35.
In this paper, for the fourth-order boundary value problem (BVP) ,0<t<1,u(0)=u(1)=u″(0)=u″(1)=0, where f:[0,1]×R→R is continuous, η≤0 is a parameter, the existence of infinitely many mountain pass solutions are obtained with the variational methods and critical point theory. We prove the conclusion by combining sub-sup solution method, Mountain pass theorem in order intervals, Leray-Schauder degree theory and Morse theory. 相似文献
36.
37.
Wanghang Gu Xianfeng Zhang Junchen Liu Jihui Zheng Haozhen Huang Linhua Jia Xinghua Qu Fumin Zhang 《Laser \u0026amp; Photonics Reviews》2024,18(2):2300831
Efficient and ultra-sensitive measurements of micro-angle are critical technological requirements in various fields. Traditional measurement approaches have disadvantages in terms of accuracy and system complexity. Here, a micro-angle measurement scheme based on the pixelated metasurface is reported. By utilizing the interaction between a C-band optical frequency comb (OFC) laser source and the plasmonic metasurface, precise angle encoding is achieved, enabling each meta-pixel within the pixelated metasurface to exhibit ultra-sensitive responses to angular changes. Experimental results demonstrate a resolution as low as 2.8 μrad for angle sensing. Furthermore, by controlling the dimensions of the meta-atom structural dimensions and designing specific combinations of meta-pixels, the unique angle response of individual pixels is manipulated, effectively creating an angle barcode. This technique allows for highly efficient acquisition of angle information, and based on this, it demonstrates absolute angle measurement with an average error at 7 μrad. The robustness and stability of the proposed scheme is also evaluated. 相似文献
38.
A mobile molecular Doppler wind lidar at an eye-safe wavelength of 355 nm based on double-edge technique is being built in Hefei (China) for wind measurement from 10-to 40-km altitude. The structure of this lidar system is described. A triple Fabry-Perot etalon is employed as a frequency discriminator whose parameters are optimized. The receiver system is designed to achieve compactness and stability by putting in a standard 19-inch socket bench. Simulation results show that within the wind speed dynamic range of ±100 m/s, the horizontal wind errors due to noise are less than 1 m/s bdow 20-km altitude for 100-m vertical resolution, and less than 5.5 m/s from 20 km up to 40 km for 500-m vertical resolution with 400-mJ laser energy, 30-min temporal resolution, and a 45-cm aperture telescooe. 相似文献
39.
40.