首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   198篇
  免费   10篇
  国内免费   1篇
化学   157篇
晶体学   3篇
力学   2篇
数学   15篇
物理学   32篇
  2024年   7篇
  2023年   4篇
  2022年   19篇
  2021年   13篇
  2020年   10篇
  2019年   20篇
  2018年   10篇
  2017年   3篇
  2016年   11篇
  2015年   8篇
  2014年   13篇
  2013年   20篇
  2012年   17篇
  2011年   17篇
  2010年   8篇
  2009年   5篇
  2008年   7篇
  2007年   6篇
  2006年   5篇
  2005年   2篇
  2002年   2篇
  1999年   1篇
  1995年   1篇
排序方式: 共有209条查询结果,搜索用时 0 毫秒
61.
In this paper, a nondifferentiable multiobjective programming problem is considered where every component of objective and constraint functions contain a term involving the support function of a compact convex set. A new class of higher order (F,α,ρ,d)-type I function is introduced. Necessary optimality conditions and the duality theorems for Wolfe and unified higher order dual problems are established. Several known results can be deduced as special cases.  相似文献   
62.
Nanostructured TiO2 in different shapes such as nanosheet, nanowire, and nanoflower, as well as nanosphere have been prepared and characterized. Nonlinear optical (NLO) properties were measured at 532 nm using open and closed aperture Z-scan technique with respect to the shape. NLO behaviour of the nanostructured TiO2 is found to be shape dependent in suspensions at the investigated wavelengths and is accounted in terms of effective surface-to-volume ratio of the structures. The values of different optical constants viz, β,n 2,χ (3) for different morphological structures were evaluated and compared. The optical limiting thresholds of the samples were also investigated and it is found to decrease with increase in the net light matter interaction area of the sample.  相似文献   
63.
Obesity is a serious health complication in almost every corner of the world. Excessive weight gain results in the onset of several other health issues such as type II diabetes, cancer, respiratory diseases, musculoskeletal disorders (especially osteoarthritis), and cardiovascular diseases. As allopathic medications and derived pharmaceuticals are partially successful in overcoming this health complication, there is an incessant need to develop new alternative anti-obesity strategies with long term efficacy and less side effects. Plants harbor secondary metabolites such as phenolics, flavonoids, terpenoids and other specific compounds that have been shown to have effective anti-obesity properties. Nanoencapsulation of these secondary metabolites enhances the anti-obesity efficacy of these natural compounds due to their speculated property of target specificity and enhanced efficiency. These nanoencapsulated and naive secondary metabolites show anti-obesity properties mainly by inhibiting the lipid and carbohydrate metabolizing enzymes, suppression of adipogenesis and appetite, and enhancing energy metabolism. This review focuses on the plants and their secondary metabolites, along with their nanoencapsulation, that have anti-obesity effects, with their possible acting mechanisms, for better human health.  相似文献   
64.
Journal of Fluorescence - A heterocyclic Schiff base (MPDPI)was synthesized by the condensation reaction of 1-phenylisatin with 4,5-dimethylphenylene diamine. It was characterized by using...  相似文献   
65.
Protein misfolding and aggregation play a significant role in several neurodegenerative diseases. In the present work, the spontaneous aggregation of hen egg-white lysozyme (HEWL) in an alkaline pH 12.2 at an ambient temperature was studied to obtain molecular insights. The time-dependent changes in spectral peaks indicated the formation of β sheets and their effects on the backbone and amino acids during the aggregation process. Introducing iodoacetamide revealed the crucial role of intermolecular disulphide bonds amidst monomers in the aggregation process. These findings were corroborated by Molecular Dynamics (MD) simulations and protein-docking studies. MD simulations helped establish and visualize the unfolding of the proteins when exposed to an alkaline pH. Protein docking revealed a preferential dimer formation between the HEWL monomers at pH 12.2 compared with the neutral pH. The combination of Raman spectroscopy and MD simulations is a powerful tool to study protein aggregation mechanisms.  相似文献   
66.
67.
Deep tissue bioimaging with three‐photon (3P) excitation using near‐infrared (NIR) light in the second IR window (1.0–1.4 μm) could provide high resolution images with an improved signal‐to‐noise ratio. Herein, we report a photostable and nontoxic 3P excitable donor‐π‐acceptor system (GMP) having 3P cross‐section (σ3) of 1.78×10?80 cm6 s2 photon?2 and action cross‐section (σ3η3) of 2.31×10?81 cm6 s2 photon?2, which provides ratiometric fluorescence response with divalent zinc ions in aqueous conditions. The probe signals the Zn2+ binding at 530 and 600 nm, respectively, upon 1150 nm excitation with enhanced σ3 of 1.85×10?80 cm6 s2 photon?2 and σ3η3 of 3.33×10?81 cm6 s2 photon?2. The application of this probe is demonstrated for ratiometric 3P imaging of Zn2+ in vitro using HuH‐7 cell lines. Furthermore, the Zn2+ concentration in rat hippocampal slices was imaged at 1150 nm excitation after incubation with GMP, illustrating its potential as a 3P ratiometric probe for deep tissue Zn2+ ion imaging.  相似文献   
68.
Journal of Radioanalytical and Nuclear Chemistry - Some of the coastal parts of Kerala are well reported high background radiation areas (HBRA). Hence, the radiological protection of the population...  相似文献   
69.
Surfactant use throughout mankind is extensive, from their initial applications as detergents extending to use in medicine, lubricant, cosmetics and even enhanced oil recovery. However, the image of surfactant use has in the past been tarnished by issues with low biodegradability and their synthesis from nonsustainable resources. Amino acid–based surfactants are a class of surfactants derived from a hydrophobe source coupled with simple amino acids, mixed amino acids from synthesis or from protein hydrolysates, and as such can be derived solely from renewable resources. There are several pathways for their synthesis and this allows for extensive structural diversity in this class of surfactants, resulting in widespread tuneable functionality in their physiochemical properties. This review includes the details of most of the available routes of synthesis for amino acid surfactants (AASs) and the impact of the diverse routes on their final physiochemical properties, including solubility, dispersability, toxicity and biodegradability. The diversity offered by the structural variation in AASs offers many exciting commercial opportunities for this ever-growing class of surfactants. It also includes a discussion on current and future potential uses of AASs.  相似文献   
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号