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   2147篇
  免费   566篇
各国政治   109篇
工人农民   3篇
世界政治   28篇
外交国际关系   216篇
法律   1687篇
中国共产党   3篇
中国政治   16篇
政治理论   543篇
综合类   108篇
  2024年   6篇
  2023年   8篇
  2022年   13篇
  2021年   53篇
  2020年   73篇
  2019年   181篇
  2018年   147篇
  2017年   127篇
  2016年   159篇
  2015年   141篇
  2014年   136篇
  2013年   309篇
  2012年   228篇
  2011年   163篇
  2010年   115篇
  2009年   132篇
  2008年   213篇
  2007年   206篇
  2006年   102篇
  2005年   39篇
  2004年   37篇
  2003年   46篇
  2002年   18篇
  2001年   11篇
  2000年   12篇
  1999年   13篇
  1998年   2篇
  1997年   3篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1993年   4篇
  1992年   3篇
  1991年   2篇
  1989年   4篇
  1986年   1篇
  1985年   1篇
  1981年   1篇
排序方式: 共有2713条查询结果,搜索用时 15 毫秒
981.
Previous work has demonstrated the ability to differentiate individuals based on the analysis of human scent hand odor chemicals. In this paper, a range of forensic biological specimens are shown to also have the ability to differentiate individuals based upon the volatile organic compounds (VOCs) present. Human VOC profiles from hand odor, oral fluid, breath, blood, and urine of 31 individuals were analyzed by solid‐phase microextraction–gas chromatography–mass spectrometry (SPME‐GC‐MS) and combined methods of chromatogram comparison, Spearman rank correlation comparison, and principal component analysis. Intra‐specimen comparisons demonstrated the distinguishability of individuals above 99%. Inter‐specimen VOC profiles from the same individual were found to be too different to be used for scent‐matching purposes, with Spearman rank coefficients below 0.15. A 6‐month VOC profile monitoring of two individuals demonstrated the consistency of VOC profiles over time across specimens.  相似文献   
982.
In the United Kingdom, theft of lead is common, particularly from churches and other public buildings with lead roofs. To assess the potential to distinguish lead from different sources, 41 samples of lead from 24 church roofs in Northamptonshire, U.K, have been analyzed for relative abundance of trace elements and isotopes of lead using X‐ray fluorescence (XRF) and inductively coupled plasma mass spectrometry, respectively. XRF revealed the overall presence of 12 trace elements with the four most abundant, calcium, phosphorus, silicon, and sulfur, showing a large weight percentage standard error of the mean of all samples suggesting variation in the weight percentage of these elements between different church roofs. Multiple samples from the same roofs, but different lead sheets, showed much lower weight percentage standard errors of the mean suggesting similar trace element concentrations. Lead isotope ratios were similar for all samples. Factors likely to affect the occurrence of these trace elements are discussed.  相似文献   
983.
The Government has recently abolished Imprisonment for Public Protection, a highly controversial form of indeterminate sentence. Yet, at the time of writing, nearly 6,000 inmates are still serving such sentences, all of whom will have to convince a Parole Board that detention is no longer necessary for the protection of the public. This paper evaluates recent European Court of Human Rights jurisprudence which considered the legality of post‐tariff detention in the absence of suitable rehabilitative provision. The Court held that there would be a violation of Article 5(1) if prisoners were held without access to such provision. Consideration is given to the implications of this ruling for those serving such sentences and, more broadly, to the impact it may have on risk‐based sentencing policies.  相似文献   
984.
目的寻找SCN2B、SCN4B基因的变异位点,探讨其与青壮年不明原因夜间睡眠中猝死(SMDS)的关系。方法提取SMDS病例组及健康对照组的基因组DNA,采用聚合酶链式反应(PCR)方法扩增SCN2B、SCN4B基因编码区外显子、外显子-内含子交界区以及3'侧翼区序列,直接行DNA测序以明确遗传变异类型。结果在病例组中共检测到4个变异位点,c.237+27AG,c.*38CT,c.174CT(p.C58C)和c.*7CT。结论本研究首次对中国人SMDS病例进行了SCN2B、SCN4B基因的检测,上述基因是否为中国人SMDS的易感基因尚有待进一步研究证实。  相似文献   
985.
将150只BALB/c小鼠随机分成5组。用猪链球菌2型pET32a-Sly、pET32a-38ku和pET32a-Sly-38ku表达的重组蛋白制备的疫苗,以及猪链球菌2型全菌灭活疫苗分别免疫A、B、C、D组小鼠,E组为生理盐水对照。首免后第2周加强免疫1次,二免后第2周,用致死量强毒猪链球菌2型四川分离株和江苏分离株以及马链球菌兽疫亚种安徽分离株攻毒,观察攻毒后对小鼠的免疫保护率。结果,A组与C、D组对猪链球菌2型感染的保护率差异显著(P<0.05),而C组与D组之间保护率无显著差异;A、B、C、D组之间对马链球菌兽疫亚种安徽分离株感染的保护率差异不显著;各免疫组的保护率极显著高于对照组。结果表明,3种重组疫苗具有良好的免疫原性,能对强毒株猪链球菌2型的攻击感染起到保护作用。  相似文献   
986.
Soil can play an important role in forensic cases in linking suspects or objects to a crime scene by comparing samples from the crime scene with samples derived from items. This study uses an adapted ED‐XRF analysis (sieving instead of grinding to prevent destruction of microfossils) to produce elemental composition data of 20 elements. Different data processing techniques and statistical distances were evaluated using data from 50 samples and the log‐LR cost (Cllr). The best performing combination, Canberra distance, relative data, and square root values, is used to construct a discriminative model. Examples of the spatial resolution of the method in crime scenes are shown for three locations, and sampling strategy is discussed. Twelve test cases were analyzed, and results showed that the method is applicable. The study shows how the combination of an analysis technique, a database, and a discriminative model can be used to compare multiple soil samples quickly.  相似文献   
987.
Researchers envisioned Storage as a Service (StaaS) as an effective solution to the distributed management of digital data. Cooperative storage cloud forensic is relatively new and is an under‐explored area of research. Using Symform as a case study, we seek to determine the data remnants from the use of cooperative cloud storage services. In particular, we consider both mobile devices and personal computers running various popular operating systems, namely Windows 8.1, Mac OS X Mavericks 10.9.5, Ubuntu 14.04.1 LTS, iOS 7.1.2, and Android KitKat 4.4.4. Potential artefacts recovered during the research include data relating to the installation and uninstallation of the cloud applications, log‐in to and log‐out from Symform account using the client application, file synchronization as well as their time stamp information. This research contributes to an in‐depth understanding of the types of terrestrial artifacts that are likely to remain after the use of cooperative storage cloud on client devices.  相似文献   
988.
This study presents the fatal case of a young man who was admitted to the ICAU due to sudden cardiac arrest. An interview revealed that the patient had taken some unspecified crystals. From the moment of admission, his condition deteriorated dramatically as a result of increasing circulatory insufficiency. After a few hours, sudden cardiac arrest occurred again and the patient was pronounced dead. In the course of a medicolegal autopsy, samples of biological material were preserved for toxicology tests and histopathological examination. The analysis of samples using the LC‐MS/MS technique revealed the presence of α‐PVP in the following concentrations: blood—174 ng/mL, urine—401 ng/mL, brain—292 ng/g, liver—190 ng/g, kidney—122 ng/g, gastric contents—606 ng/g. The study also presents findings from the parallel histopathological examination. Based on these findings, cardiac arrest secondary to intoxication with alpha‐PVP was determined as the direct cause of the patient's death.  相似文献   
989.
A rapid colorimetric method for detection of p‐phenylenediamine (PPD) in various biological samples is developed. The o‐cresol test for acetaminophen detection has been modified to detect PPD in blood, urine, gastric contents, and liver. After precipitating protein with trichloroacetic acid solution (2 mL, 10% w/v), biological specimens were required to convert PPD metabolites to PPD by acid hydrolysis. Finally, o‐cresol solution (1 mL, 1% w/v), hydrogen peroxide (200 μL, 3%v/v), and concentrated ammonium hydroxide (0.5 mL) were added in the biological samples. The presence of PPD was indicated by formation of violet color which was turned to bluish green color within 10–15 min. The limit of detection was found to be 2 mg/L in blood, urine, and gastric contents and 2 mg/Kg in liver. This method is also free from any potential interference by p‐aminophenol, acetaminophen, and other amine drugs under test conditions. This method was successfully employed to thirteen fatal cases of PPD poisoning.  相似文献   
990.
Crime scene investigators and laboratory analysts use chemical tests to detect and differentiate body fluids. Testing often requires a sample of the stain, and the chemicals may cause degradation of the fluid or interfere with subsequent tests. Colorimetric chemical tests do not differentiate between different types of the same fluid, such as venous and menstrual blood, and there is no presumptive test available to simultaneously differentiate several body fluids. In this study, we recorded ATR FT ‐IR spectra of venous and menstrual blood, semen, saliva, and breastmilk. Neat and simulated casework body fluid samples were analyzed on cotton, nylon, wood, paper, and glass substrates. Differences in fluid composition, including proteins and small molecules, resulted in spectral differences. Venous and menstrual blood is differentiated by the peak at 1039 cm?1 attributed to phosphoric acid found in menstrual blood. Peak intensity is influenced by the porosity and weave of the substrate fabric.  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