全文获取类型
收费全文 | 104篇 |
免费 | 7篇 |
国内免费 | 20篇 |
专业分类
化学 | 98篇 |
力学 | 7篇 |
综合类 | 2篇 |
数学 | 4篇 |
物理学 | 20篇 |
出版年
2023年 | 3篇 |
2022年 | 11篇 |
2021年 | 7篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 1篇 |
2015年 | 8篇 |
2014年 | 6篇 |
2013年 | 9篇 |
2012年 | 9篇 |
2011年 | 9篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 2篇 |
1999年 | 2篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有131条查询结果,搜索用时 250 毫秒
81.
Let {X n }n?≥?1 be a sequence of strictly stationary m-dependent random variableswith EX1 = 0 and \( \mathrm{E}{X}_1^2<\infty \), and let (b n ) be an increasing sequence of positive numbers such that b n ?↑?∞ and \( {b}_n/\sqrt{n}\downarrow 0\kern0.5em \mathrm{as}\kern0.5em n\to \infty \). We establish a moderate deviation principle of \( {\left({b}_n\sqrt{n}\right)}^{-1}{\sum}_{i=1}^n{X}_i \) under the condition
which is weaker than the classical exponential integrability condition. The results in the present paper weaken the assumptions of Chen [5] and extend partially the results of Eichelsbacher and Löwe [10]. 相似文献
$$ \underset{n\to \infty }{\lim \sup}\frac{1}{b_n^2}\log \left[n\mathbf{P}\left(\left|{X}_1\right|>{b}_n\sqrt{n}\right)\right]=-\infty, $$
82.
This paper is concerned with the existence of a global attractor for a semiflow governed by the weak solutions to a nonlinear one-dimensional thermoviscoelasticity with a non-convex free energy density. The constitutive assumptions for the Helmholtz free energy include the model for the study of martensitic phase transitions in shape memory alloys. To describe physically phase transitions between different configurations of crystal lattices, we work in a framework in which the strain u belongs to L∞. New approaches are introduced and more delicate estimates are derived to establish the crucial L∞-estimate of strain u in deriving the compactness of the orbit of the semiflow and the existence of an absorbing set. 相似文献
83.
核壳结构CdS/ZnS纳米微粒的制备与光学特性 总被引:6,自引:0,他引:6
用微乳液法制备CdS纳米微粒 ,以ZnS对其进行表面修饰 ,得到具有核壳结构的CdS/ZnS纳米微粒 .采用X射线衍射 (XRD)、透射电镜 (TEM )表征其结构、粒度和形貌 ,紫外 可见吸收光谱 (UV)、光致发光光谱(PL)表征其光学特性 .制得的CdS近似呈球形 ,直径为 3.3nm ;以XRD和UV证实了CdS/ZnS核壳结构的实现 .研究了不同ZnS壳层厚度对CdS纳米微粒光学性能的影响 ,UV谱表明随着壳层厚度的增加纳米微粒的吸收带边有轻微的红移 ,同时短波吸收增强 ;PL谱表明壳层ZnS的包覆可减少CdS纳米微粒的表面缺陷 ,带边直接复合发光的几率增大 ,具有合适的壳层厚度时发光效率大大提高 . 相似文献
84.
85.
Guorui Yang Wei Yan Jianan Wang Qian Zhang Honghui Yang 《Journal of Sol-Gel Science and Technology》2014,71(1):159-167
SrTiO3 nanofibers were successfully prepared by a facile electrospinning method with subsequent calcination in air. These one dimensional nanostructures were characterized for the morphological, structural and optical properties by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV–visible diffuse reflectance spectroscopy. The photocatalytic investigations showed that the SrTiO3 nanofibers possessed enhanced photocatalytic efficiency in photodegradation of rhodamine B and photocatalytic H2 evolution from water splitting under ultraviolet light irradiation, compared with the SrTiO3 nanoparticles and P25. The enhanced photocatalytic performance can be ascribed to the beneficial microstructure and more negative conduction band edge compared with P25. 相似文献
86.
Fabrication of Two‐Dimensional Lateral Heterostructures of WS2/WO3⋅H2O Through Selective Oxidation of Monolayer WS2 下载免费PDF全文
Pengshang Zhou Prof. Qun Xu Hongxiang Li Dr. Yun Wang Bo Yan Dr. Yunchun Zhou Dr. Jiafu Chen Dr. Jianan Zhang Kaixi Wang 《Angewandte Chemie (International ed. in English)》2015,54(50):15226-15230
Two‐dimensional (2D) lateral heterostructures have emerged as a hot topic in the fast evolving field of advanced functional materials , but their fabrication is challenging. The layer‐structured WS2 was theoretically demonstrated to be inert to oxidation except for the monolayer, which can be selectively oxidized owing to the simultaneous interaction of oxygen with both sides. Combined with the theoretical calculations, a new method was developed for the successful construction of 2D lateral heterostructures of WS2/WO3?H2O in an ambient environment, based on a simple liquid‐phase solution exfoliation. These lateral heterostructures of WS2/WO3?H2O have interesting properties, as indicated by enhanced photocatalytic activity toward the degradation of methyl orange (MO). 相似文献
87.
Wenpei Fan Wenbo Bu Zhen Zhang Bo Shen Hui Zhang Qianjun He Dalong Ni Zhaowen Cui Kuaile Zhao Jiwen Bu Jiulin Du Jianan Liu Jianlin Shi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(47):14232-14236
Multifunctional stimuli‐responsive nanotheranostic systems are highly desirable for realizing simultaneous biomedical imaging and on‐demand therapy with minimized adverse effects. Herein, we present the construction of an intelligent X‐ray‐controlled NO‐releasing upconversion nanotheranostic system (termed as PEG‐USMSs‐SNO) by engineering UCNPs with S‐nitrosothiol (R‐SNO)‐grafted mesoporous silica. The PEG‐USMSs‐SNO is designed to respond sensitively to X‐ray radiation for breaking down the S N bond of SNO to release NO, which leads to X‐ray dose‐controlled NO release for on‐demand hypoxic radiosensitization besides upconversion luminescent imaging through UCNPs in vitro and in vivo. Thanks to the high live‐body permeability of X‐ray, our developed PEG‐USMSs‐SNO may provide a new technique for achieving depth‐independent controlled NO release and positioned radiotherapy enhancement against deep‐seated solid tumors. 相似文献
88.
89.
Wenbing Hu Qun Luo Dr. Xiaoyan Ma Kui Wu Jianan Liu Yi Chen Prof. Dr. Shaoxiang Xiong Dr. Jianping Wang Prof. Dr. Peter J. Sadler Prof. Dr. Fuyi Wang Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(27):6586-6594
Arene control : Anticancer complexes [Ru(arene)Cl(en)]+ (arene=p‐cymene or biphenyl; en=ethylenediamine) bind to surface histidine (His128, His247, His510) and methionine (Met298) residues in human albumin, but only the p‐cymene complex can gain entry to the crevice containing the free cysteine thiolate (Cys34) and induce oxidation to sulfinate.
90.
A spectroscopy system is developed for studying the two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) of epithelial tissue in backscattering geometry. Our findings show that TPEF signals from epithelial and underlying stromal layers exhibit different spectral characteristics, providing information on the biomorphology and biochemistry of tissue. The SHG signal serves as a sensitive indicator of collagen to separate the epithelial layer from underlying stroma. The polarization dependence of the SHG signal reveals a well-ordered orientation of collagen fibers in the stromal layer. The results demonstrate the potential of depth-resolved TPEF and SHG in determining the pathology of epithelial tissue. 相似文献