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   454篇
  免费   36篇
各国政治   15篇
工人农民   21篇
世界政治   27篇
外交国际关系   35篇
法律   226篇
中国政治   15篇
政治理论   147篇
综合类   4篇
  2023年   7篇
  2022年   6篇
  2021年   4篇
  2020年   10篇
  2019年   31篇
  2018年   29篇
  2017年   29篇
  2016年   26篇
  2015年   23篇
  2014年   28篇
  2013年   58篇
  2012年   33篇
  2011年   22篇
  2010年   16篇
  2009年   26篇
  2008年   18篇
  2007年   21篇
  2006年   23篇
  2005年   9篇
  2004年   15篇
  2003年   9篇
  2002年   13篇
  2001年   6篇
  2000年   3篇
  1999年   5篇
  1998年   2篇
  1997年   3篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1988年   1篇
  1985年   1篇
排序方式: 共有490条查询结果,搜索用时 15 毫秒
361.
This study was designed to supplement previous studies that documented in vitro production of gamma-hydroxybutyrate (GHB) in urine samples. Urine samples were provided by subjects who reported that they had never used GHB (n=31). The specimens were stored under standard conditions of refrigeration (5 degrees C) without any preservatives added. All specimens were repeatedly analyzed for the presence of endogenous GHB over a 6-month period using a previously reported headspace GC-MS method. Significant elevations in GHB were observed in many of the urine samples as storage time increased. As a result, the in vitro production of GHB may increase the apparent GHB concentrations in urine during storage. This potential for an artificial increase in GHB concentration must be appreciated when establishing the threshold between endogenous and exogenous concentrations of GHB.  相似文献   
362.
A great deal of research has suggested that scholarly and popular concerns about low levels of citizen political knowledge are exaggerated. One implication of that research is that political history would have unfolded just as it did even if electorates had been more politically informed. This paper presents evidence that counters these claims, showing an infusion of electorally relevant information in twenty-seven democracies would have likely led to a lot of vote “switching”, ultimately changing the composition of many governments. The paper also directly and systematically examines what we might call the “enlightened natural constituency” hypothesis, which expects lower-income citizens to vote disproportionately for left parties once armed with more political knowledge. While the basic argument about how political ignorance disproportionately affects the left’s natural constituency is not new, the hypothesis has thus far not been tested. The analysis provides provisional support for the hypothesis.  相似文献   
363.
364.
Abstract: The AutoMate Express? Forensic DNA Extraction System was developed for automatic isolation of DNA from a variety of forensic biological samples. The performance of the system was investigated using a wide range of biological samples. Depending on the sample type, either PrepFiler? lysis buffer or PrepFiler BTA? lysis buffer was used to lyse the samples. After lysis and removal of the substrate using LySep? column, the lysate in the sample tubes were loaded onto AutoMate Express? instrument and DNA was extracted using one of the two instrument extraction protocols. Our study showed that DNA was recovered from as little as 0.025 μL of blood. DNA extracted from casework‐type samples was free of detectable PCR inhibitors and the short tandem repeat profiles were complete, conclusive, and devoid of any PCR artifacts. The system also showed consistent performance from day‐to‐day operation.  相似文献   
365.
Prior studies in Drug Courts reported improved outcomes when participants were matched to schedules of judicial status hearings based on their criminological risk level. The current experiment determined whether incremental efficacy could be gained by periodically adjusting the schedule of status hearings and clinical case-management sessions in response to participants' ensuing performance in the program. The adjustments were made pursuant to a priori criteria specified in an adaptive algorithm. Results confirmed that participants in the full adaptive condition (n = 62) were more than twice as likely as those assigned to baseline-matching only (n = 63) to be drug-abstinent during the first 18 weeks of the program; however, graduation rates and the average time to case resolution were not significantly different. The positive effects of the adaptive program appear to have stemmed from holding noncompliant participants more accountable for meeting their attendance obligations in the program. Directions for future research and practice implications are discussed.  相似文献   
366.
Hair testing for drugs of abuse is performed in Lombardy by eleven analytical laboratories accredited for forensic purposes, the most frequent purposes being driving license regranting and workplace drug testing. Individuals undergoing hair testing for these purposes can choose the laboratory in which the analyses have to be carried out. The aim of our study was to perform an interlaboratory exercise in order to verify the level of standardization of hair testing for drugs of abuse in these accredited laboratories; nine out of the eleven laboratories participated in this exercise. Sixteen hair strands coming from different subjects were longitudinally divided in 3-4 aliquots and distributed to participating laboratories, which were requested to apply their routine methods. All the participants analyzed opiates (morphine and 6-acetylmorphine) and cocainics (cocaine and benzoylecgonine) while only six analyzed methadone and amphetamines (amphetamine, methamphetamine, MDMA, MDA and MDEA) and five Δ(9)-tetrahydrocannabinol (THC). The majority of the participants (seven labs) performed acidic hydrolysis to extract the drugs from the hair and analysis by GC-MS, while two labs used LC-MS/MS. Eight laboratories performed initial screening tests by Enzyme Multiplied Immunoassay Technique (EMIT), Enzyme-linked Immunosorbent Assay (ELISA) or Cloned Enzyme Donor Immunoassay (CEDIA). Results demonstrated a good qualitative performance for all the participants, since no false positive results were reported by any of them. Quantitative data were quite scattered, but less in samples with low concentrations of analytes than in those with higher concentrations. Results from this first regional interlaboratory exercise show that, on the one hand, individuals undergoing hair testing would have obtained the same qualitative results in any of the nine laboratories. On the other hand, the scatter in quantitative results could cause some inequalities if any interpretation of the data is required.  相似文献   
367.
A review of the literature concerning the fate and behavior of gunshot residue (GSR) is presented. A number of concomitant parameters including firearm and ammunition type, plume and GSR material characteristics, travel distances, chemical composition and GSR morphology are critically discussed in relation to their effects on the distribution and deposition, transfer and persistence processes of GSR. The underlying mechanisms associated with such processes are also considered. Knowledge of these processes on GSR materials could provide valuable information concerning scene preservation and subsequent forensic sampling. The number of GSR particles deposited can vary significantly with each firearm discharge, highlighting the potential to produce distinctive data in each individual case. With the continual development and compositional changes of new ammunition types, further evaluation of the effect these processes may have on GSR evidence and their possible influence on the interpretation of the analytical results should be given due consideration.  相似文献   
368.
Correctional officers work in a highly challenging environment and are at a heightened risk of a range of negative stress-related health conditions. This study examines how correctional officer responses to adversity moderate the association between perceived workplace adversity and psychological well-being. The aim was to assess the degree that perceived workplace adversity predicts correctional officer psychological well-being and the subsequent impact on negative organizational outcomes such as absenteeism, presenteeism and job dissatisfaction. Hundred and seventy four officers completed an online questionnaire including measures of perceived workplace adversity, officer responses, psychological well-being and organizational impact. Structural Equation Modelling revealed that a heightened perception of workplace adversity predicted lower psychological well-being and in turn increased negative organizational impacts. Analyses indicated that using an interpersonal/solution focused response style moderated the relationship between perceived workplace adversity and psychological well-being, reducing its negative impact on well-being and in turn the frequency of negative organizational impacts. These findings offer insight into how officers’ perceptions of their working environment and how they respond to workplace adversity influence their psychological well-being and the organizations that employ them.  相似文献   
369.
370.
The present study employed multilevel random-effects regression analyses to model individual and community correlates of youth supplying tobacco to other minors. Data from 8486 youth in 40 Midwestern junior high and high schools were examined. Results indicate community support for tobacco-possession laws was associated with lower likelihood of youth supplying tobacco to minors. Individual attitudes supporting tobacco possession laws were also associated with lower likelihood of supplying tobacco. Recent smoking, using a social source or purchasing tobacco in the past month, successfully purchasing tobacco during the last attempt to buy it, and having friends who use tobacco were associated with an increased likelihood of supplying tobacco to minors. Results also suggest that purchasing tobacco in the past month or being successful during the last attempt to buy it dramatically increase the odds of supplying tobacco among Never and Past Smokers. Implications of these findings are presented.
Steven B. PokornyEmail:
  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