全文获取类型
收费全文 | 84836篇 |
免费 | 629篇 |
国内免费 | 426篇 |
专业分类
化学 | 29398篇 |
晶体学 | 849篇 |
力学 | 6890篇 |
综合类 | 1篇 |
数学 | 32774篇 |
物理学 | 15979篇 |
出版年
2023年 | 52篇 |
2022年 | 78篇 |
2021年 | 150篇 |
2020年 | 142篇 |
2019年 | 126篇 |
2018年 | 10494篇 |
2017年 | 10312篇 |
2016年 | 6237篇 |
2015年 | 1014篇 |
2014年 | 505篇 |
2013年 | 672篇 |
2012年 | 4271篇 |
2011年 | 11004篇 |
2010年 | 5917篇 |
2009年 | 6242篇 |
2008年 | 7025篇 |
2007年 | 9203篇 |
2006年 | 712篇 |
2005年 | 1782篇 |
2004年 | 1929篇 |
2003年 | 2299篇 |
2002年 | 1275篇 |
2001年 | 338篇 |
2000年 | 363篇 |
1999年 | 220篇 |
1998年 | 256篇 |
1997年 | 218篇 |
1996年 | 310篇 |
1995年 | 175篇 |
1994年 | 138篇 |
1993年 | 156篇 |
1992年 | 98篇 |
1991年 | 90篇 |
1990年 | 75篇 |
1989年 | 82篇 |
1988年 | 97篇 |
1987年 | 82篇 |
1986年 | 89篇 |
1985年 | 109篇 |
1984年 | 80篇 |
1983年 | 61篇 |
1982年 | 91篇 |
1981年 | 65篇 |
1980年 | 68篇 |
1979年 | 70篇 |
1978年 | 66篇 |
1977年 | 46篇 |
1973年 | 41篇 |
1914年 | 45篇 |
1909年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
In the paper, the authors establish several integral representations for the generating functions of the large and little Schröder numbers and for the large and little Schröder numbers. 相似文献
2.
Mesoscopic modeling at the pore scale offers great promise in exploring the underlying structure transport performance of flow through porous media. The present work studies the fluid flow subjected to capillarity-induced resonance in porous media characterized by different porous structure and wettability. The effects of porosity and wettability on the displacement behavior of the fluid flow through porous media are discussed. The results are presented in the form of temporal evolution of percentage saturation and displacement of the fluid front through porous media. The present study reveals that the vibration in the form of acoustic excitation could be significant in the mobilization of fluid through the porous media. The dependence of displacement of the fluid on physicochemical parameters like wettability of the surface, frequency along with the porosity is analyzed. It was observed that the mean displacement of the fluid is more in the case of invading fluid with wetting phase where the driving force strength is not so dominant. 相似文献
3.
4.
Sarah Peluse 《Israel Journal of Mathematics》2018,227(1):379-396
We prove that the group of diffeomorphisms of the interval [0, 1] contains surface groups whose action on (0, 1) has no global fix point and such that only countably many points of the interval (0, 1) have non-trivial stabiliser. 相似文献
5.
6.
Control over Nanostructures and Associated Mesomorphic Properties of Doped Self‐Assembled Triarylamine Liquid Crystals 下载免费PDF全文
Dr. Yuya Domoto Dr. Eric Busseron Prof. Dr. Mounir Maaloum Dr. Emilie Moulin Prof. Dr. Nicolas Giuseppone 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(5):1938-1948
We have synthesized a series of triarylamine‐cored molecules equipped with an adjacent amide moiety and dendritic peripheral tails in a variety of modes. We show by 1H NMR and UV/Vis spectroscopy that their supramolecular self‐assembly can be promoted in solution upon light stimulation and radical initiation. In addition, we have probed their molecular arrangements and mesomorphic properties in the bulk by integrated studies on their film state by using differential scanning calorimetry (DSC), variable‐temperature polarizing optical microscopy (VT‐POM), variable‐temperature X‐ray diffraction (VT‐XRD), and atomic force microscopy (AFM). Differences in the number and the disposition of the peripheral tails significantly affect their mesomorphic properties associated with their lamellar‐ or columnar‐packed nanostructures, which are based on segregated stacks of the triphenylamine cores and the lipophilic/lipophobic periphery. Such structural tuning is of interest for implementation of these soft self‐assemblies as electroactive materials from solution to mesophases. 相似文献
7.
8.
9.
10.
Foundations of Chemistry - 相似文献