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   217篇
  免费   8篇
各国政治   13篇
工人农民   12篇
世界政治   18篇
外交国际关系   6篇
法律   118篇
中国政治   2篇
政治理论   42篇
综合类   14篇
  2021年   1篇
  2020年   4篇
  2019年   2篇
  2018年   8篇
  2017年   6篇
  2016年   7篇
  2015年   7篇
  2014年   6篇
  2013年   42篇
  2012年   10篇
  2011年   9篇
  2010年   4篇
  2009年   7篇
  2008年   6篇
  2007年   11篇
  2006年   11篇
  2005年   4篇
  2004年   9篇
  2003年   11篇
  2002年   9篇
  2001年   2篇
  2000年   5篇
  1999年   1篇
  1998年   2篇
  1997年   5篇
  1996年   4篇
  1995年   2篇
  1994年   1篇
  1993年   3篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
  1986年   1篇
  1984年   1篇
  1983年   3篇
  1982年   1篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1972年   3篇
  1971年   1篇
  1966年   1篇
排序方式: 共有225条查询结果,搜索用时 31 毫秒
11.
The aims of this study are to identify the most powerful predictors of school dropout and to determine how stable they are over time. Two generations of White French-speaking boys and girls from 12 to 16 years old (n = 791 in 1974, n = 791 in 1985) completed a self-administered questionnaire on their psychosocial adjustment at least one year before leaving school. As expected, the analyses showed that school, family, behavioral, social, and personality variables could all predict dropping out of school in the two samples. Furthermore, these predictors were quite stable over time. However, statistical improvement measures in logistic regression analyses indicated that school experience variables (i.e., grade retention, school achievement, school commitment) were the best screening variables for potential dropouts. The contribution of other psychosocial variables, even though significant, did not improve very much the capacity to identify who will drop out of school. The discussion highlights the implications of the findings for secondary prevention and screening practices.  相似文献   
12.
13.
14.
Hepp U  Wittmann L  Schnyder U  Michel K 《危机》2004,25(3):108-117
A literature search was conducted to collect randomized controlled studies evaluating the outcome of psychological and psychosocial interventions after attempted suicide and deliberate self-harm. Twenty-five studies meeting the inclusion criteria were identified. The studies are grouped according to the psychological approach chosen for the intervention. They are discussed with regard to both the various therapeutic strategies and models used, and the repetition of self-harming behavior as the main outcome.  相似文献   
15.
The amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy" is a currently used or abused designer drug and fatalities are frequently encountered in forensic practice. However, the question remains open whether an MDMA blood level can be toxic or even potentially lethal. In order to provide insight in the interpretation of a detected MDMA concentration, the distribution of MDMA and its metabolite 3,4-methylenedioxyamphetamine (MDA) in various body fluids and tissues was studied and discussed in two different fatalities. Apart from peripheral blood samples (such as femoral and subclavian blood), various blood samples obtained centrally in the human body and several body fluids (such as vitreous humour) were examined. In addition, various tissues such as cardiac muscle, lungs, liver, kidneys, and brain lobes were analysed. In contrast to the peripheral blood levels, high MDMA and MDA levels were found in cardiac blood and the majority of the organs, except for the abdominal adipose tissue. The high concentrations observed in all lung lobes, the liver and stomach contents indicate that post-mortem redistribution of MDMA and MDA into cardiac blood can occur and, as a result, blood sampled centrally in the body should be avoided. Therefore, our data confirm that peripheral blood sampling remains "the golden standard". In addition, a distinct difference in peripheral blood MDMA concentrations in our two overdose cases was established (namely 0.271 and 13.508 microg/ml, respectively). Furthermore, our results suggest that, if a peripheral blood sample is not available and when putrefaction is not too pronounced, vitreous humour and iliopsoas muscle can be valuable specimens for toxicological analysis. Finally, referring to the various mechanisms of death following amphetamine intake, which can result in different survival times (e.g. cardiopulmonary complications versus hyperthermia), the anatomo-pathological findings and the toxicological results should be considered as a whole in arriving at a conclusion.  相似文献   
16.
A rapid and sensitive method using LC-MS/MS triple stage quadrupole for the determination of traces of amphetamine (AP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”), 3,4-methylenedioxyethamphetamine (MDEA), and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB) in hair, blood and urine has been developed and validated. Chromatography was carried out on an Uptisphere ODB C18 5 μm, 2.1 mm × 150 mm column (Interchim, France) with a gradient of acetonitrile and formate 2 mM pH 3.0 buffer. Urine and blood were extracted with Toxitube A® (Varian, France). Segmented scalp hair was treated by incubation 15 min at 80 °C in NaOH 1 M before liquid–liquid extraction with hexane/ethyl acetate (2/1, v/v). The limits of quantification (LOQ) in blood and urine were at 0.1 ng/mL for all analytes. In hair, LOQ was <5 pg/mg for MA, MDMA, MDEA and MBDB, at 14.7 pg/mg for AP and 15.7 pg/mg for MDA. Calibration curves were linear in the range 0.1–50 ng/mL in blood and urine; in the range 5–500 pg/mg for MA, MDMA, MDEA and MBDB, and 20–500 pg/mg for AP and MDA. Inter-day precisions were <13% for all analytes in all matrices. Accuracy was <20% in blood and urine at 1 and 50 ng/mL and <10% in hair at 20 and 250 pg/mg. This method was applied to the determination of MDMA in a forensic case of single administration of ecstasy to a 16-year-old female without her knowledge during a party. She suffered from hyperactivity, sweating and agitation. A first sample of urine was collected a few hours after (T + 12 h) and tested positive to amphetamines by immunoassay by a clinical laboratory. Blood and urine were sampled for forensic purposes at day 8 (D + 8) and scalp hair at day 60 (D + 60). No MDMA was detected in blood, but urine and hair were tested positive, respectively at 0.42 ng/mL and at 22 pg/mg in hair only in the segment corresponding to the period of the offence, while no MDA was detectable. This method allows the detection of MDMA up to 8 days in urine after single intake.  相似文献   
17.
18.
19.
20.
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