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   20866篇
  免费   297篇
各国政治   933篇
工人农民   650篇
世界政治   1634篇
外交国际关系   938篇
法律   12319篇
中国共产党   3篇
中国政治   120篇
政治理论   4451篇
综合类   115篇
  2021年   131篇
  2020年   340篇
  2019年   414篇
  2018年   466篇
  2017年   552篇
  2016年   562篇
  2015年   470篇
  2014年   494篇
  2013年   2200篇
  2012年   445篇
  2011年   560篇
  2010年   524篇
  2009年   555篇
  2008年   538篇
  2007年   485篇
  2006年   516篇
  2005年   491篇
  2004年   504篇
  2003年   461篇
  2002年   470篇
  2001年   790篇
  2000年   711篇
  1999年   557篇
  1998年   334篇
  1997年   268篇
  1996年   235篇
  1995年   242篇
  1994年   280篇
  1993年   261篇
  1992年   364篇
  1991年   402篇
  1990年   364篇
  1989年   391篇
  1988年   338篇
  1987年   344篇
  1986年   378篇
  1985年   367篇
  1984年   286篇
  1983年   312篇
  1982年   226篇
  1981年   244篇
  1980年   170篇
  1979年   260篇
  1978年   173篇
  1977年   148篇
  1976年   150篇
  1975年   108篇
  1974年   148篇
  1973年   143篇
  1972年   118篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Juvenile delinquency has been on the decline for a number of years, yet, juvenile courts continue to assess more than 1 million cases per year. Involvement with the juvenile justice system has been linked to a number of risk factors and consequences that may impact positive youth development; however, evidence-based correctional programs that divert juvenile offenders away from formal processing are limited. Teen Court is a specialized diversion intervention that offers an alternative to traditional court processing for juvenile offenders. Despite the rapid expansion of Teen Courts, there is little comprehensive and systematic evidence available to justify this expansion. This meta-analytic study examines the effects of Teen Court on the recidivism of juvenile offenders. The literature search resulted in the selection of 14 studies, which contributed 18 unique effect sizes with a total sample of 2125 treatment group and 979 comparison group youth. The findings suggest that Teen Court is no more effective at reducing recidivism than (a) formal processing or (b) other diversion programs. Implications of formal and informal court processing for low-risk, first-time young offenders are discussed. The authors draw on the Risk-Need-Responsivity model to provide recommendations for policies and practices.  相似文献   
992.
Youth’s career attainment is associated with socioeconomic background, but may also be related to their beliefs about causes of success. Relationships between 17-year-olds’ socioeconomic status (SES) and causal beliefs about success, and whether these beliefs predict career attainment after completing a vocational or university degree were examined using data from the German Socio-Economic Panel Study (n?=?997, 48.5% female). Youth with higher SES parents and those who attended higher levels of high schools were less likely to believe that success in society is due to external causes, but SES was unrelated to the belief that success is due to personal merit or ability. Youth who believe that success is due to external causes attained lower income, occupational prestige, and job autonomy, and slower increases in income over time. There were also significant indirect effects of youth’s parents’ SES and their own high school levels on career attainment through such external causal beliefs; merit beliefs, by contrast, were largely unrelated to career attainment. These results suggest that beliefs about external causes of success may uniquely contribute to the transmission and maintenance of SES across generations and over time.  相似文献   
993.
This study reports findings from an evaluation of a new generation jail in a large southwestern state. The jail is one component of a complex containing a traditional jail, an indirect supervision facility (barracks), and the new generation jail. Using survey and operational data, we compare the new generation jail to the other two facilities. The findings provide generally positive support for the effectiveness of the new generation jail. Inmates and staff were much more satisfied with the physical facilities. Staff perceived it as more secure, though they reported only limited advantages in safety and security. Violence and disciplinary problems were substantially lower. However, no savings in staffing levels were noted, nor were there differences in job satisfaction for staff in the new generation jail. We discuss the implications of the findings and suggest additional directions for jail evaluations.  相似文献   
994.
995.
In order to establish an animal model for entomotoxicological studies, the kinetics of morphine elimination from blood after a single intravenous injection of morphine and the concentration of morphine in tissues following a continuous perfusion were studied. The aim of these experiments was to obtain controlled morphine tissue concentrations similar to those encountered in fatal human heroin overdoses. These tissues can be used as a food source for developing fly larvae in entomotoxicological studies. In the single injection experiment, seven rabbits were administered 1 or 2 mg/kg body weight of morphine chlorhydrate via the main ear artery. Blood samples of 200 microL were removed regularly via a catheter. Morphine concentration was determined using RIA techniques. Morphine was found to be first rapidly distributed and then slowly eliminated, following a two-exponential equation. Elimination of morphine from blood can be described as a two-compartment model. Constants of the equation were determined using the Kaleidagraph program. Using those constants, the main pharmacokinetics parameters were calculated. Results of these parameters showed the following: clearance from 13.3 to 16.2 L.h.1, half-life of the distribution phase from 0.6 to 0.9 min, and half-life of the elimination phase from 21 to 26 min. These results were used to calculate the rate of perfusion of morphine for rabbits to obtain desired, controlled, and constant concentrations of morphine in tissues. In the second experiment, three rabbits received a perfusion of morphine intravascularly at a rate of 2 mg/kg/h for a period of 3 h. These rabbits were sacrificed and analyses performed on several abdominal and thoracic organs. Results showed that the concentrations of morphine differed according to the organ analyzed, but were reproducible for organs between animals. These concentrations were similar to those normally encountered in cases of human death due to heroin overdoses.  相似文献   
996.
997.
998.
A statistical investigation of the relationship between firing range and the amount and distribution of gunshot residue (GSR), used automated image analysis (IA) to quantify GSR deposit resulting from firings into pig skin, from distances ranging between contact and 45 cm. Overall, for a Ruger .22 semi-automatic rifle using CCI solid point, high velocity ammunition, the total area of GSR deposit on the skin sections decreased in a non-linear fashion with firing range. More specifically there were significant differences in the amount of GSR deposited from shots fired at contact compared with shots fired from distances between 2.5 and 45 cm; and between shots fired from a distance of 20 cm or less, with shots fired at a distance of 30 cm or more. In addition, GSR particles were heavily concentrated in the wound tract only for contact and close range shots at 2.5 cm, while the particle distribution was more uniform between the wound tract and the skin surfaces for shots fired from distances greater than 2.5 cm. Consequently, for future scientific investigations of gunshot fatalities, once standards have been established for the weapon and ammunition type in question, image analysis quantification of GSR deposited in and around the gunshot wound may be capable of providing a reliable, statistical basis for estimating firing range.  相似文献   
999.
Prostate specific antigen (PSA, also known as p30), a glycoprotein produced by the prostatic gland and secreted into seminal plasma, is a marker used for demonstrating the presence of seminal fluid. Methods for the detection of PSA include Ouchterlony double diffusion, crossover electrophoresis, rocket immuno-electrophoresis, radial immunodiffusion, and ELISA. The extremely sensitive ELISA technique can detect PSA in concentrations as low as approximately 4 ng/mL. However, all these techniques are cumbersome and time consuming to perform in forensic laboratories, especially when only a few samples per week are processed. Various membrane tests are currently used in clinical settings to screen a patient's serum for the presence of PSA at levels greater than 4 ng/mL. In this study we evaluated three immunochromatographic PSA membrane tests by analyzing semen stains stored at room temperature for up to 30 years, post-coital vaginal swabs taken at different time after intercourse, semen-free vaginal swabs, and various female and male body fluids, including urine. The data demonstrate that PSA membrane test assays offer the same sensitivity as ELISA-based tests and provide a rapid approach for the forensic identification of seminal fluid. Furthermore, when the supernatant from a DNA extraction is used for the assay, there is essentially no DNA consumption for determining the presence of PSA in a forensic sample.  相似文献   
1000.
Accidental hypothermia has been described in the forensic literature but reports of occurrence in hospitalized patients are rare. Associated anatomic lesions include acute hemorrhagic pancreatitis and characteristic acute gastric ulcers termed Wischnewski ulcers. We report here two patients with cirrhosis and ascites; one also had hepatocellular carcinoma. Portal vein thrombosis, acute hemorrhagic pancreatitis and Wischnewski ulcers were present in both. The clinical records documented hypothermia that progressed over several days. Temperature nadirs of 31.0 degrees C (87.8 degrees F) and 32.2 degrees C (90.0 degrees F) were recorded in each patient, respectively, one day before death, although each transiently reached temperatures that did not register on standard monitoring devices. This is the first report that chronicles antemortem body temperatures in hypothermic patients with Wischnewski ulcers and pancreatitis at autopsy. Also, the association of these findings with portal vein thrombosis and cirrhosis has not been previously described. We discuss this constellation of findings with regard to possible mechanistic interrelations.  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