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   595篇
  免费   9篇
各国政治   18篇
工人农民   53篇
世界政治   72篇
外交国际关系   29篇
法律   299篇
中国政治   3篇
政治理论   127篇
综合类   3篇
  2024年   4篇
  2023年   9篇
  2022年   4篇
  2021年   8篇
  2020年   19篇
  2019年   22篇
  2018年   33篇
  2017年   25篇
  2016年   28篇
  2015年   24篇
  2014年   15篇
  2013年   78篇
  2012年   25篇
  2011年   15篇
  2010年   15篇
  2009年   31篇
  2008年   16篇
  2007年   15篇
  2006年   16篇
  2005年   26篇
  2004年   17篇
  2003年   23篇
  2002年   18篇
  2001年   17篇
  2000年   14篇
  1999年   9篇
  1998年   3篇
  1997年   7篇
  1996年   3篇
  1995年   7篇
  1994年   5篇
  1993年   6篇
  1992年   4篇
  1991年   5篇
  1990年   2篇
  1989年   3篇
  1988年   2篇
  1987年   3篇
  1986年   5篇
  1985年   3篇
  1984年   2篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1978年   3篇
  1977年   3篇
  1975年   2篇
  1973年   2篇
排序方式: 共有604条查询结果,搜索用时 0 毫秒
351.
    
Mitragyna speciosa (MS), a plant commonly known as kratom, is a widely used “legal high” opiate alternative for pain relief. DNA extracted from MS and 26 additional plant species was amplified by PCR using primers targeting the strictosidine beta-D-glucosidase (SGD) and secologanin synthase 2 (SLS2) genes and detected by high-resolution melt curves using three intercalating dyes. Amplicon sizes were confirmed using agarose gel electrophoresis. The observed melt temperatures for SGD and SLS2 were 77.08 ± 0.38°C and 77.61 ± 0.46°C, respectively, using SYBR® Green I; 80.18 ± 0.27°C and 80.59 ± 0.08°C, respectively, using Radiant Green; and 82.19 ± 0.04°C and 82.62 ± 0.13°C, respectively, using the LCGreen® PLUS dye. The SLS2 primers demonstrated higher specificity and identified MS DNA at 0.05 ng/μL. In a duplex reaction, SLS2 and tetrahydrocannabinoic acid synthase gene primers detected and differentiated MS and Cannabis sativa (CS) by melt peaks at 82.63 ± 0.35°C and 85.58 ± 0.23°C, respectively, using LCGreen® PLUS.  相似文献   
352.
    
During fingerprint comparisons, a latent print examiner visually compares two impressions to determine whether or not they originated from the same source. They consider the amount of perceived detail in agreement or disagreement and accumulate evidence toward same source and different sources propositions. This evidence is then mapped to one of three conclusions: Identification, Inconclusive, or Exclusion. A limitation of this 3-conclusion scale is it can lose information when translating the conclusion from the internal strength-of-evidence value to one of only three possible conclusions. An alternative scale with two additional values, support for different sources and support for common sources, has been proposed by the Friction Ridge Subcommittee of OSAC. The expanded scale could lead to more investigative leads but could produce complex trade-offs in both correct and erroneous identifications. The aim of the present study was to determine the consequences of a shift to expanded conclusion scales in latent print comparisons. Latent print examiners each completed 60 comparisons using one of the two scales, and the resulting data were modeled using signal detection theory to measure whether the expanded scale changed the threshold for an “Identification” conclusion. When using the expanded scale, examiners became more risk-averse when making “Identification” decisions and tended to transition both the weaker Identification and stronger Inconclusive responses to the “Support for Common Source” statement. The results demonstrate the utility of an expanded conclusion scale and also provide guidance for the adoption of these or similar scales.  相似文献   
353.
A quick, simple, and high-yield nucleic acid isolation process is crucial for high-quality DNA analysis. The ability of the MicroGEM PDQeX phytoGEM system and Omega Bio-tek E.Z.N.A.® Plant DS Mini kit to extract PCR-ready DNA was evaluated by extracting the forensically relevant “legal high” plant species: Ipomoea purpurea, Artemisia absinthium, Mitragyna speciosa, Datura stramonium, and Papaver somniferum. The plant material was pulverized, processed using the manufacturer’s plant protocol for the PDQeX Nucleic Acid Extraction or the manufacturer’s protocol for the Omega extraction, quantified using the Invitrogen Qubit 2.0 Fluorometer, and analyzed for amplifiability by PCR using a Qiagen Rotor-Gene Q instrument and published assays. The DNA amplicons for the legal high species produced high-resolution melt curves concordant with the melts observed when DNA was isolated using the Qiagen DNeasy Plant Mini Kit in previous studies.  相似文献   
354.
    
The use of alternative light sources (ALS) in bloodstain analysis has focused on dried (whole) blood, while information on detection of blood serum is lacking. Serum detection by ALS could provide valuable information at a crime scene, as serum may become separated from blood during clotting and cast off, especially in cases where the victim is moved. Additionally, a perpetrator may concentrate on the removal/scouring of dried blood with small amounts of serum going unnoticed, as it dries relatively clear on certain objects. In this report, the detection of human blood serum was evaluated using ultraviolet (UV) light at two different wavelengths. These results show that ultraviolet (UV) at 365 nm (UV365) was effective in the detection of even small amounts of blood plasma and serum, compared with UV at 395 nm, which was not. UV365 was also found to be useful in distinguishing blood imprints from clotting blood which had been transferred to material versus blood that had been added directly. Taken together, these results demonstrate that UV365 may be utilized as a simple, nondestructive method for blood serum detection.  相似文献   
355.
    
Forensic pathologist use soot and/or stippling surrounding entrance gunshot wounds in categorizing range of fire. If absent, some pathologists suggest utilizing histology when the range is diagnostically critical. This study investigates the concordance of macroscopic and microscopic findings in estimating range of fire by evaluating gunshot entrance and exit wounds made through human tissue analogs at defined distances using two handgun calibers. Examination of over 150 entrance wounds verified the ease of visually detecting soot from a muzzle distance of contact to 1 foot (30.5 cm), and its absence at 9 feet (274.3 cm). Distinctly apparent was bullet wipe surrounding the entrance wounds regardless of muzzle distance. Although variations existed, dark material was histologically identified in many skin, soft tissue, and bone sections at all ranges with both calibers. These nonparallel results decrease the dependability of histology for range of fire estimation and reinforce using gross observation.  相似文献   
356.
    
Artemisia absinthium (wormwood), a common ingredient in absinthe, contains the compound thujone, which is unregulated by the U.S. Drug Enforcement Agency. Thujone can cause an “unregulated legal high” in higher concentrations. The European Union limits thujone from Artemisia species to 35 mg/kg while the U.S. Food and Drug Administration requires less than 10 ppm to be “thujone‐free.” However, individuals can smoke or ingest A. absinthium in different forms. This study developed a polymerase chain reaction (PCR) high‐resolution melt (HRM) assay to detect and identify A. absinthium based on primer specificity, sensitivity, repeatability, and robustness. A triplex assay was performed with three “unregulated legal high” species: Datura stramonium, Merremia tuberosa, and A. absinthium; the PCR HRM assay detected and identified each plant at melt temperatures 77.42 ± 0.20°C, 83.88 ± 0.22°C, and 87.77 ± 0.15°C, respectively. The primer set developed distinguished A. absinthium from a variety of plant species and was successfully triplexed.  相似文献   
357.
ABSTRACT

The parental monitoring literature has long observed a link between parental monitoring and juvenile antisocial behaviour. This study extends this line of research to juveniles who commit sexual abuse. The present study investigates whether juvenile reports of parental monitoring differ between juvenile sexual offenders (n?=?338), juvenile delinquents (n?=?346), and non-incarcerated juvenile controls (n?=?256). Results indicate that both incarcerated groups reported significantly less parental knowledge compared to juvenile controls. Further, both juvenile sexual offenders and juvenile controls reported significantly more parental control compared to juvenile delinquents. With regard to parental solicitation, the results were mixed for sexual offenders. They reported high levels of solicitation for some items (e.g. what the youth was doing, who they were with), and lower levels for other items (e.g. where the youth was, whether an adult would be present). When repeating these analyses with the exclusion of non-parent caregivers, a similar pattern of results emerged; however, item-level analyses revealed that parents of juvenile delinquents reported certain types of solicitation and control behaviours more frequently (e.g. asked where the youth was going, made sure the rules were followed) compared to findings from the main sample. Potential explanations for these findings as well as practical implications for prevention are discussed.  相似文献   
358.
    
Abstract

The Crisis Intervention Team (CIT) model is an established training program used to improve police response to encounters involving persons with mental illness (PwMI). Diversion of PwMI from the criminal justice system to appropriate treatment providers in the community is one of the primary goals of CIT. The present study examines characteristics and outcomes of encounters between citizens experiencing mental health-related crises and CIT-trained patrol officers. Findings of this study indicate encounters involving PwMI and CIT-trained officers often result in diversion to mental health services. Implications for policy and future research are discussed.  相似文献   
359.
360.
    
With the adoption of statutes, policies and administrative guidance since the late 1980s, statutory child welfare agencies around the world have been implementing practice approaches to resolving and addressing child abuse and neglect concerns that involve extended family systems in decision making and planning. One such approach is the family group conference (FGC), enshrined in New Zealand law. This article provides a historical context and describes numerous provisions of the family group conference that protect participants and the proceedings. It then describes applications of FGC‐like approaches in the United States where practice models and policies—not laws—guide the implementation of such approaches.  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