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   23篇
  免费   3篇
工人农民   2篇
法律   16篇
政治理论   2篇
综合类   6篇
  2023年   1篇
  2019年   2篇
  2018年   1篇
  2017年   1篇
  2015年   1篇
  2014年   1篇
  2013年   5篇
  2012年   2篇
  2011年   1篇
  2010年   3篇
  2008年   4篇
  2007年   1篇
  2005年   1篇
  2003年   1篇
  1999年   1篇
排序方式: 共有26条查询结果,搜索用时 15 毫秒
1.
Making cross-groups comparisons by using survey instruments has raised substantial scholarly concerns due to the potential risk of incomparability resulting from differential item functioning (DIF). However, not every survey item necessarily suffers from DIF. In this paper, we argue that, unlike many other survey items (e.g., political efficacy), the usual question used to measure political interest is likely to be largely immune to DIF. Our theoretical argument centers on the relative specificity of the item and a corresponding cultural homogeneity (at least in advanced democracies) in what it means to be politically interested or not. Utilizing the anchoring vignettes technique (King et al., 2004; King and Wand, 2007) in our original surveys in the UK, France, and the Netherlands, we demonstrate the size of DIF is small for the standard political interest question.  相似文献   
2.
Over the past decades, consume of slimming agents considerably increased in several countries, including Brazil, due to weight-loss and stimulant properties. Since these drugs are controlled to prevent illicit and indiscriminate use, there is a parallel illegal market that uses the Internet and irregular pharmacies in order to distribute these formulations. Slimming agents produced by these illegal sources are known for being manufactured with little or none quality control resulting in uncertain and unknown formulations. For forensic purposes, apprehended pharmaceuticals have to undergo a process of chemical identification that can be difficult due to its complex matrix. In this sense, application of assisted energies in the extraction step such as microwave irradiation can be a promising method to increase the recuperation of the target molecules of the sample. Therefore, the aim of this research was to identify four slimming agents apprehended in Brazil by means of visual inspection, Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry and Gas Chromatography – Mass Spectrometry. Moreover, the efficiency of solid-liquid extraction and microwave-assisted extraction was compared. It should be noted that our work was one of the few to use Differential Scanning Calorimetry and the application of microwave irradiation in the analysis of apprehended materials. Results showed that the majority of the samples was counterfeit being composed of one or several adulterants or contaminants. Initially, visual inspection resourcefully screened the slimming agents for possible signs of falsification, however it failed to detect fraudulent products that were very similar to veridical medicines. Sequentially, Fourier Transform Infrared Spectroscopy detected functional groups present in the samples while the presence or absence of the alleged active ingredients were successfully measured with Differential Scanning Calorimetry and, thus, providing a full chemical screening of the apprehended materials. Gas Chromatography- Mass Spectrometry confirmed the presence of adulterants such as caffeine, fluoxetine and phenolphthalein as well as contaminants such as sulfurol in the falsified samples. Finally, comparison of extraction procedures indicated that microwave-assisted extraction increased the recovery of compounds detected in chromatographic analysis to a greater extent than solid-liquid extraction.  相似文献   
3.
DNase-Ⅰ纯化结合碱性裂解法提取混合斑精子DNA   总被引:1,自引:0,他引:1  
目的研究脱氧核糖核酸酶I(DNase-I)纯化结合碱性裂解法提取混合斑精子DNA的方法在法医学中的应用。方法收集79份性犯罪案件混合斑检材,分别用DNase-I纯化结合碱性裂解法和差异裂解法提取精子DNA,采用STR荧光标记复合扩增体系进行16个STR基因座分型,并比较检验结果。结果应用DNase-I纯化结合碱性裂解法提取精子DNA,64例检材分型成功;应用差异裂解法提取精子DNA,57例检材分型成功;两种方法比较结果存在显著性差异(P=0.039),DNase-1纯化结合碱性裂解法提取精子DNA的STR分型成功率更高,成本低廉。结论DNase-I纯化结合碱性裂解法提取混合斑精子DNA可提高检验成功率,操作简便,快速,易于自动化,适于法医学个体识别鉴定。  相似文献   
4.
《TRIPs协议修正案》的出台有一定的历史背景。它的诞生也会对差别定价制产生显著的进一步影响。该《修正案》的出台促使了全球差别定价制的发展。差别定价制中的发达国家完全补偿类型、发展中国家支付专利使用费补偿类型和最不发达国家零补偿类型也会受到该《修正案》的影响。这些影响的构成有一定的政治、经济和法律原因。  相似文献   
5.
目的 探讨微小RNA(microRNA,miRNA)在复发性流产(repeated spontaneous abortion,RSA)肾虚证小鼠子宫蜕膜组织中的表达特征。方法 运用基因芯片技术对所采集的正常对照组和RSA小鼠蜕膜组织进行miRNA检测,运用Genespring软件对miRNA进行筛选及功能分析。应用生物信息学方法分析差异表达的miRNA及其靶向基因在RSA发生、发展中的作用。结果 芯片检测结果显示正常对照组和RSA肾虚证组筛选出差异表达的miRNA共有63条(22条上调、41条下调),实时荧光定量PCR验证的miRNA的表达情况与miRNA芯片结果一致。京都基因与基因组百科全书通路富集分析及基因本体分析显示,其差异表达的miRNA涉及到PI3K-Akt信号通路、细胞吞噬通路、癌症通路、黏着斑通路、肌动蛋白细胞骨架调控通路、轴突导向信号、MAPK信号通路、PAP-1信号通路等。结论 RSA肾虚证小鼠子宫蜕膜组织中存在差异表达的micro RNA,可能涉及RSA肾虚证的发生、发展。  相似文献   
6.
So far we have little by way of a theoretical understanding of the dynamics of electoral competition. This paper attempts to fill some of this gap by studying resource expenditure over the electoral cycle. Among the main results is that, when contributions from donors are independent of support, parties accelerate expenditure during the entire period between elections, even when voters do not forget. If contributions depend on support, and are significant, parties front load expenditure and decelerate.  相似文献   
7.
Proteinase K is used in forensic DNA extraction methods for cell lysis and degradation of proteins. Here we compare Proteinase K with a novel protease. We conclude that there is no need to exchange Proteinase K in our methods.  相似文献   
8.
We present a rapid alkaline lysis procedure for the extraction of DNA from sexual assault evidence that generates purified sperm fraction extracts that yield STR typing results similar to those obtained from the traditional organic/dithiothreitol differential extraction. Specifically, a sodium hydroxide based differential extraction method has been developed in a single-tube format and further optimized in a 96-well format. The method yields purified extracts from a small sample set (∼2-6 swabs) in approximately 2 h and from a larger sample set (up to 96 swabs) in approximately 4 h. While conventional differential extraction methods require vigorous sample manipulation to remove the spermatozoa from the substrate, the method described here exploits the propensity of sperm to adhere to a substrate and does not require any manipulation of the substrate after it is sampled. For swabs, sample handling is minimized by employing a process where the tip of the swab, including the shaft, is transferred to the appropriate vessel eliminating the need for potentially hazardous scalpels to separate the swab material from the shaft. The absence of multiple handling steps allows the process to be semi-automated, however the procedure as described here does not require use of a robotic system. This method may provide forensic laboratories a cost-effective tool for the eradication of backlogs of sexual assault evidence, and more timely service to their client agencies. In addition, we have demonstrated that a modification of the procedure can be used to retrieve residual sperm-cell DNA from previously extracted swabs.  相似文献   
9.
In sexual assault cases DNA profiling of spermatozoa can be of critical importance. Most methods use differential extraction of the spermatozoa to separate it from the female component. Here we have compared two commercially available differential extraction methods, the QIAamp® DNA mini kit (Qiagen) and Differex™ with the DNA IQ® System (Promega). Simulated postcoital samples were prepared using buccal cells from a female donor and spermatozoa from three male donors. A dilution series ranging from neat semen to a 1:1500 dilution (semen:dH2O) was prepared and mixed with an equal volume of saliva from a female donor. Extraction efficiency was assessed using DNA concentration measured with NanoDrop 2000 and Quantifiler® Human DNA Quantification Kit and the profile count of full, partial and mixed DNA profiles generated using SGM Plus and PowerPlex® ESI 17. Statistical analysis was carried out using Randomisation in R, which is a robust model making no assumption of the distribution of data. Based on the amount of DNA extracted and the types of profiles no significant difference in the performance of the two extraction kits was seen. However, the processing time taken with the Differex™ System was about half than that of the QIAamp® DNA mini kit and involved fewer liquid transfers.  相似文献   
10.
The present study examined the moderating effect of the quality of the sibling relationship on the longitudinal association of parental treatment with theft, vandalism, and violence in adolescence. Participants were 416 sibling pairs which were studied over a one-year period. The younger siblings were aged 13 to 15, the older siblings 14 to 17 at Time 1. No significant effects were found for mixed-sex dyads. For same-sex dyads, the results suggested that when the relationship was of poor quality, younger boys who felt treated less favorably by their mothers were most likely to show high levels of vandalism and violence, while younger girls who felt treated less favorably were most likely to show high levels of theft. No such effects were found for older siblings. These findings indicate that differential parental treatment and the quality of the sibling relationship have gender-specific effects on adolescents’ delinquency and have a different meaning for younger than for older siblings.
Ron. H. J. ScholteEmail:
  相似文献   
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