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   298篇
  免费   7篇
  国内免费   1篇
化学   206篇
晶体学   1篇
力学   15篇
数学   19篇
物理学   65篇
  2023年   1篇
  2022年   2篇
  2021年   12篇
  2020年   10篇
  2019年   7篇
  2018年   7篇
  2017年   6篇
  2016年   14篇
  2015年   10篇
  2014年   11篇
  2013年   10篇
  2012年   23篇
  2011年   41篇
  2010年   11篇
  2009年   13篇
  2008年   20篇
  2007年   29篇
  2006年   17篇
  2005年   16篇
  2004年   7篇
  2003年   7篇
  2002年   11篇
  2001年   1篇
  2000年   2篇
  1999年   4篇
  1996年   7篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1988年   1篇
  1982年   1篇
  1974年   1篇
排序方式: 共有306条查询结果,搜索用时 31 毫秒
1.
Journal of Thermal Analysis and Calorimetry - This work aims to investigate the thermal decomposition and reaction kinetics of the hybrid energy cane, as well as its thermochemical properties....  相似文献   
2.
Three reduced graphene oxide nanocomposites were employed to achieve the simultaneous electrochemical determination of multi-drugs including acetaminophen (ACTM), carbendazim (CB) and ciprofloxacin (CFX). All nanocomposite modified electrodes showed improved current responses for three drugs. Notably cauliflower-like platinum nanoparticles decorated reduced graphene oxide modified electrode (or Pt−RGO/GCE) exhibited the best performance in terms of electrochemical stability. Using Pt−RGO/GCE, the linear detect ranges of 30–120 μM, 25–115 μM and 10–25 μM, and detection limit values of 3.49, 2.96, and 1.53 μM were achieved for ACTM, CB and CFX respectively. The electrode was further used for the successful determination of above drugs in tap and river water using differential pulse voltammetry. From the obtained results, we believe that Pt-RGO/GCE is highly promising for the fabrication of robust electrochemical sensors for simultaneously determining ACTM, CB and CFX or similar types of drugs in the future.  相似文献   
3.
We study existence and uniqueness of solutions for a general class of second order abstract differential equations with state-dependent delay. Some examples related to partial differential equations with state dependent delay are presented.  相似文献   
4.
Gold nanoparticles (AuNPs) were prepared by chemical route using four different protocols by varying reducer, stabilizing agent, and solvent mixture. The obtained AuNPs were characterized by transmission electronic microscopy (TEM), UV-visible, and zeta potential measurements. From these latter, surface charge densities σ were calculated to evidence the effect of the solvent mixture on AuNP stability. The AuNPs were then deposited onto glassy carbon (GC) electrodes by drop casting, and the resulting deposits were characterized by cyclic voltammetry (CV) in H2SO4 and field emission gun scanning electron microscopy (FEG-SEM). The electrochemical kinetic parameters of the four different modified electrodes toward oxygen reduction reaction (ORR) in neutral NaCl-NaHCO3 media (0.15 M/0.028 M, pH 7.4) were evaluated by rotating disk electrode voltammetry and subsequent Koutecky-Levich treatment. Contrary to what we previously obtained with electrodeposited AuNPs [Gotti et al., Electrochim. Acta 2014], the highest cathodic transfer coefficients β were not obtained on the smallest particles, highlighting the influence of the stabilizing ligand together with the deposit morphology on the ORR kinetics.  相似文献   
5.
Most real core-shell nanoparticle (CSNP) samples deviate from an ideal core-shell structure potentially having significant impact on the particle properties. An ideal structure displays a spherical core fully encapsulated by a shell of homogeneous thickness, and all particles in the sample exhibit the same shell thickness. Therefore, analytical techniques are required that can identify and characterize such deviations. This study demonstrates that by analysis of the inelastic background in X-ray photoelectron spectroscopy (XPS) survey spectra, the following types of deviations can be identified and quantified: the nonuniformity of the shell thickness within a nanoparticle sample and the incomplete encapsulation of the cores by the shell material. Furthermore, CSNP shell thicknesses and relative coverages can be obtained. These results allow for a quick and straightforward comparison between several batches of a specific CSNP, different coating approaches, and so forth. The presented XPS methodology requires a submonolayer distribution of CSNPs on a substrate. Poly(tetrafluoroethylene)-poly(methyl methacrylate) and poly(tetrafluoroethylene)-polystyrene polymer CSNPs serve as model systems to demonstrate the applicability of the approach.  相似文献   
6.
We report the synthesis and characterization of a water‐soluble, star‐shaped macromolecular platform consisting of eight β‐cyclodextrin (β‐CD) units anchored to the narrower rim of a γ‐CD core through bis(triazolyl)alkyl spacers. The efficient synthetic protocol is based on the microwave (MW)‐promoted Cu‐catalyzed 1,3‐dipolar cycloaddition of CD monoazides to CD monoacetylenes. The ligand‐hosting capability of the construct has been assessed by relaxometric titration and nuclear magnetic relaxation dispersion (NMRD) profiling, which showed it to be good, and this was supported by molecular dynamics simulations. To demonstrate the feasibility of obtaining supramolecular structures with high hosting ability, we designed a dimeric platform, formed by joining two nonamers through the γ‐CD cores through a bis(lithocholic acid) linker. With a view to the potential biological applications, cytotoxicity and extent of binding to human serum albumin were assessed. The properties of this dendrimeric multicarrier make it suitable for pharmaceutical and diagnostic purposes, ranging from targeted drug delivery to molecular imaging.  相似文献   
7.
Abstract

Functional magnetic resonance imaging of the human brain in action presents large statistical and computational challenges. Here we describe those challenges and provide references to a number of other papers where detailed methods developed to meet them are reported. The first seven sections of this paper were written in 1995 when our work was in its infancy. The last four sections were written more recently, to update the earlier sections and to show the directions we have gone and the directions we intend to go.  相似文献   
8.
The growing numbers related to plastic pollution are impressive, with ca. 70 % of produced plastic (>350 tonnes/year) being indiscriminately wasted in the environment. The most dangerous forms of plastic pollution for biota and human health are micro- and nano-plastics (MNPs), which are ubiquitous and more bioavailable. Their elimination is extremely difficult, but the first challenge is their detection since existing protocols are unsatisfactory for microplastics and mostly absent for nanoplastics. After a discussion of the state of the art for MNPs detection, we specifically revise the techniques based on photoluminescence that represent very promising solutions for this problem. In this context, Nile Red staining is the most used strategy and we show here its pros and limitations, but we also discuss other more recent approaches, such as the use of fluorogenic probes based on perylene-bisimide and on fluorogenic hyaluronan nanogels, with the added values of biocompatibility and water solubility.  相似文献   
9.
10.
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