全文获取类型
收费全文 | 1426篇 |
免费 | 32篇 |
国内免费 | 3篇 |
专业分类
化学 | 765篇 |
晶体学 | 30篇 |
力学 | 68篇 |
数学 | 194篇 |
物理学 | 404篇 |
出版年
2022年 | 19篇 |
2021年 | 31篇 |
2020年 | 19篇 |
2019年 | 20篇 |
2018年 | 15篇 |
2017年 | 19篇 |
2016年 | 43篇 |
2015年 | 34篇 |
2014年 | 50篇 |
2013年 | 86篇 |
2012年 | 81篇 |
2011年 | 84篇 |
2010年 | 57篇 |
2009年 | 45篇 |
2008年 | 70篇 |
2007年 | 89篇 |
2006年 | 72篇 |
2005年 | 58篇 |
2004年 | 42篇 |
2003年 | 40篇 |
2002年 | 38篇 |
2001年 | 25篇 |
2000年 | 19篇 |
1999年 | 14篇 |
1998年 | 20篇 |
1997年 | 18篇 |
1996年 | 28篇 |
1995年 | 14篇 |
1994年 | 15篇 |
1993年 | 17篇 |
1992年 | 13篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 19篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 12篇 |
1985年 | 14篇 |
1984年 | 13篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 17篇 |
1979年 | 12篇 |
1978年 | 8篇 |
1976年 | 9篇 |
1975年 | 13篇 |
1974年 | 6篇 |
1972年 | 7篇 |
1965年 | 5篇 |
排序方式: 共有1461条查询结果,搜索用时 359 毫秒
51.
52.
53.
The synthesis of the methyl esters of optically pure trans and cis 4-guanidinocyclohexylglycine as rigid analogues of D-arginine methyl ester are described. 相似文献
54.
Marco Lopez Fabio Sacconi Matthias Auf der Maur Alessandro Pecchia Aldo Di Carlo 《Optical and Quantum Electronics》2012,44(3-5):89-94
In this work electronic and optoelectronic properties of InGaN/GaN nanocolumn quantum disk LEDs have been studied with the multiscale simulation tool tiberCAD. Calculations have been performed with an atomistic tight-binding model. Results shows that emission energies have a minor dependence on the nanocolumn dimension while In concentration in the active region is a critical parameter. 相似文献
55.
Jorge L. Flores Gastón A. Ayubi Julia R. Alonso Ariel Fernández J. Matías Di Martino José A. Ferrari 《Optik》2013
We present a hybrid method for segmentation of intensity images, which combines an optical contouring technique and digital algorithms for linking edge points or image segmentation. In a first stage, the digital image to be processed is displayed in a twisted-nematic liquid-crystal display (LCD), which is placed between a polarizer–analyzer pair at 45 deg (instead of 90 deg as occurs in standard LCDs). It is not difficult to demonstrate that the proposed setup produces a resultant image with very pronounced dark contours at middle intensity. After the optical preprocessing, two different digital algorithms are applied: an edge linking algorithm (modified chain code) and a simple thresholding technique for image segmentation. The proposed procedure works well with monochromatic and color images. The method could be useful as a robust technique for segmentation of large images in real-time, which presents potential applications in medical and biological imaging. 相似文献
56.
We show that a planar BV homeomorphism can be approximated in the area strict sense, together with its inverse, with smooth or piecewise affine homeomorphisms. 相似文献
57.
58.
59.
Desirée Gentilini Alessio Gagliardi Aldo Di Carlo 《Optical and Quantum Electronics》2012,44(3-5):155-160
In this work we present a numerical simulation of a dye solar cell efficiency using a drift-diffusion model for the complete cell. The physical parameters such as the active layer thickness, the electron mobility and the dye spectrum are varied systematically in a range of values individuated experimentally, in order to obtain efficiency maps that reveal interesting features in this kind of devices. 相似文献
60.
I. Bernagozzi S. Torrengo L. Minati M. Ferrari A. Chiappini C. Armellini L. Toniutti L. Lunelli G. Speranza 《Colloid and polymer science》2012,290(4):315-322
Recently, superhydrophobic surfaces are gaining much interest because they may be employed in a series of applications, spanning
from the realization of self-cleaning surfaces to microfluidics to special water-impermeable tissues allowing perspiration.
It is well-known that superhydrophobicity strictly depends on the combination of superficial micro- and nano-structures. Then,
key factors in the process of surface synthesis are the parameters which will define the surface conformation. In this work,
we deal with the fabrication of polymer-based superhydrophobic surfaces. We developed a new method to have a good control
of the structure of the synthesised surface. A high stability of the superhydrophobic character during time was obtained.
Moreover, the synthesis process is green and easily transferable to industry for large production. 相似文献