全文获取类型
收费全文 | 80993篇 |
免费 | 855篇 |
国内免费 | 806篇 |
专业分类
化学 | 26504篇 |
晶体学 | 806篇 |
力学 | 6886篇 |
综合类 | 35篇 |
数学 | 32193篇 |
物理学 | 16230篇 |
出版年
2023年 | 83篇 |
2022年 | 72篇 |
2021年 | 84篇 |
2020年 | 133篇 |
2019年 | 137篇 |
2018年 | 10520篇 |
2017年 | 10331篇 |
2016年 | 6190篇 |
2015年 | 981篇 |
2014年 | 475篇 |
2013年 | 564篇 |
2012年 | 4085篇 |
2011年 | 10809篇 |
2010年 | 5846篇 |
2009年 | 6209篇 |
2008年 | 6816篇 |
2007年 | 8948篇 |
2006年 | 389篇 |
2005年 | 1452篇 |
2004年 | 1625篇 |
2003年 | 2041篇 |
2002年 | 1082篇 |
2001年 | 321篇 |
2000年 | 344篇 |
1999年 | 214篇 |
1998年 | 251篇 |
1997年 | 202篇 |
1996年 | 260篇 |
1995年 | 187篇 |
1994年 | 113篇 |
1993年 | 117篇 |
1992年 | 87篇 |
1991年 | 93篇 |
1990年 | 66篇 |
1989年 | 74篇 |
1988年 | 73篇 |
1987年 | 63篇 |
1986年 | 65篇 |
1985年 | 56篇 |
1984年 | 47篇 |
1983年 | 39篇 |
1982年 | 47篇 |
1981年 | 45篇 |
1980年 | 48篇 |
1979年 | 48篇 |
1914年 | 45篇 |
1913年 | 40篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 70 毫秒
1.
Guo-Xing Li Xiao-Wei Qu Lu-Wei Hao Qing Li Su Chen 《Journal of polymer science. Part A, Polymer chemistry》2022,60(11):1710-1717
From the implementation point of view, the printable magnetic Janus colloidal photonic crystals (CPCs) microspheres are highly desirable. Herein, we developed a dispensing-printing strategy for magnetic Janus CPCs display via a microfluidics-automatic printing system. Monodisperse core/shell colloidal particles and magnetic Fe3O4 nanoparticles precursor serve as inks. Based on the equilibrium of three-phase interfacial tensions, Janus structure is successfully formed, followed by UV irradiation and self-assembly of colloid particle to generate magnetic Janus CPCs microspheres. Notably, this method shows distinct superiority with highly uniform Janus CPCs structure, where the TMPTA/Fe3O4 hemisphere is in the bottom side while CPCs hemisphere is in the top side. Thus, by using Janus CPCs microspheres with two different structural colors as pixel points, a pattern with red flower and green leaf is achieved. Moreover, 1D linear Janus CPCs pattern encapsulated by hydrogel is also fabricated. Both the color and the shape can be changed under the traction of magnets, showing great potentials in flexible smart displays. We believe this work not only offers a new feasible pathway to construct magnetic Janus CPCs patterns by a dispensing-printable fashion, but also provides new opportunities for flexible and smart displays. 相似文献
2.
Acta Mechanica Sinica - 相似文献
3.
Design of diamond-shape photonic crystal fiber polarization filter based on surface plasma resonance effect 下载免费PDF全文
A novel plasmonic polarization filter based on the diamond-shape photonic crystal fiber(PCF) is proposed. The resonant coupling characteristics of the PCF polarization filter are investigated by the full-vector finite-element method. By optimizing the geometric parameters of the PCF, when the fiber length is 5 mm, the polarization filter has a bandwidth of 990 nm and an extinction ratio(ER) of lower than -20 dB. Moreover, a single wavelength polarization filter can also be achieved, along with an ER of -279.78 dB at wavelength 1.55 μm. It is believed that the proposed PCF polarization filter will be very useful in laser and optical communication systems. 相似文献
4.
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
5.
为了寻求新型蚜虫控制剂,以蚜虫报警信息素(E)-β-farnesene(EBF)为先导,引入不同类型的杂环取代EBF结构中不稳定的共轭双键,设计合成了一系列不同杂环取代的EBF类似物.所有化合物结构均通过1H NMR、13C NMR、IR及HRMS确证.对化合物进行了生物活性测试及初步构效关系分析.结果表明,所有化合物均对桃蚜和大豆蚜表现出一定的生物活性,部分化合物的杀虫活性优于先导EBF,酯基的引入则对驱避活性有利. 相似文献
6.
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
7.
8.
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
9.
10.