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   5888篇
  免费   138篇
各国政治   241篇
工人农民   234篇
世界政治   469篇
外交国际关系   209篇
法律   3705篇
中国政治   51篇
政治理论   1093篇
综合类   24篇
  2021年   40篇
  2020年   71篇
  2019年   105篇
  2018年   138篇
  2017年   119篇
  2016年   120篇
  2015年   74篇
  2014年   122篇
  2013年   596篇
  2012年   145篇
  2011年   159篇
  2010年   129篇
  2009年   143篇
  2008年   171篇
  2007年   158篇
  2006年   141篇
  2005年   137篇
  2004年   157篇
  2003年   133篇
  2002年   105篇
  2001年   314篇
  2000年   281篇
  1999年   195篇
  1998年   83篇
  1997年   80篇
  1996年   55篇
  1995年   57篇
  1994年   54篇
  1993年   40篇
  1992年   121篇
  1991年   143篇
  1990年   136篇
  1989年   130篇
  1988年   121篇
  1987年   129篇
  1986年   106篇
  1985年   95篇
  1984年   97篇
  1983年   85篇
  1982年   57篇
  1981年   73篇
  1980年   38篇
  1979年   73篇
  1978年   46篇
  1975年   39篇
  1974年   49篇
  1973年   55篇
  1972年   39篇
  1971年   36篇
  1970年   29篇
排序方式: 共有6026条查询结果,搜索用时 15 毫秒
881.
In TLC screenings of 335 urine samples taken because of suspicion of heroin consumption, positive evidence of morphine was found in about 50% of the cases, which was confirmed without exception by gas chromatography-mass spectrometry. In 66% of the positive cases, morphine and codeine were found; in about 31% only morphine was found, and the median value of 0.4 mg/l free morphine and 1.0 mg/l conjugated morphine was considerably lower than in the whole collection of samples. Comparison of the codeine/morphine quotients (Q), especially the free bases, proves that the groups of heroin/morphine or codeine consumers can be distinctly differentiated. The critical conditions of the conjugated bases worked out by Dutt et al. (1983) proved to be right. Using the equation Qf less than 0.5 square root c, a boundary condition for the free flare bases can also be developed, which is dependent on the sum of the codeine and morphine concentrations and which proves heroin/morphine consumption with 98% certainty.  相似文献   
882.
883.
A prospective study of 161 victims of falls from height is reported. The aim was to determine the interest of systematic qualitative and quantitative toxicological analysis in such fatalities. The primary cause of death was suicide (84.5%), followed by accidents (7%) and homicide (1%). In the remaining 7.5%, cause of death was undetermined. In the suicides, there was evidence of psychotropic medicines in 57% of the observations, with a much higher proportion of benzodiazepines and antidepressants in women than in men. Quantitative toxicologic analysis showed overdosing on medication in 16 suicide victims, with toxic levels in 11 of these. Systematic qualitative and quantitative toxicologic analysis made a significant contribution to the diagnosis of suicide by revealing either an unknown psychiatric treatment or a toxic level.  相似文献   
884.
This study examined the association of victimization in a physically violent dating relationship with risk behaviors, age of risk behavior initiation, and co-occurrence of risk behaviors among students in grades 9 through 12 in the United States. Data were from the 2003 national Youth Risk Behavior Survey (YRBS). Nearly 9% of students reported experiencing dating violence victimization. Dating violence victimization was associated with alcohol use, marijuana use, and having ever had sexual intercourse among female students and having ever had sexual intercourse among male students. Dating violence victimization also was associated with early initiation of alcohol use among female students. The odds of dating violence victimization increased as the number of risk behaviors increased and as the number of lifetime sexual partners increased. These risk behavior patterns should serve as warning signs of elevated risk for dating violence victimization and may be helpful in identifying adolescents who could benefit from targeted, preventive interventions.  相似文献   
885.
This study sought to determine the screening practices of child and adolescent psychiatrists regarding adolescent dating violence (DV). A questionnaire regarding screening practices for DV and other risk behaviors was administered to 817 child and adolescent psychiatrists via the Internet and mail. Twenty-one percent of clinicians screened for DV "more than 90% of the time," and 65% had identified it in the past year. Multiple logistic regression analyses found that screening for DV was associated with consistent screening for either substance use or interparental violence (OR=3.0 and 6.3, respectively). Despite the prevalence of DV, only a minority of psychiatrists screen their adolescent patients for this type of risk. These data suggest that screening for DV is associated with consistent screening practices for other risk behaviors. Screening rates may be improved with training and adherence to specific protocols.  相似文献   
886.
Partner violence may have significant consequences on women's employment, yet limited information is available about how women cope on the job with perpetrators' tactics and the consequences of her coping methods on employment status. This article investigates whether there is an association between workplace disclosure of victimization and current employment status; and whether there is an association between receiving workplace support and current employment status among women who disclosed victimization circumstances to someone at work. Using a sample of partner victimized women who were employed within the past year (N = 485), cross-tabulation and ANOVA procedures were conducted to examine the differences between currently employed and unemployed women. Binary logistic regressions were conducted to examine whether disclosure and receiving workplace support were significantly associated with current employment. Results indicate that disclosure and workplace support are associated with employment. Implications for clinical practice, workplace policies, and future research are discussed.  相似文献   
887.
In general research suggests partner violence has a negative impact on women's employment. However, there has been limited examination of partner stalking and consequences for employment. The purpose of this study was to examine partner stalking and employment consequences among two samples of women. One sample was women who had obtained a protective order against a violent partner and had worked in the prior year (n = 482), about one half of these women were stalked by their violent partner and one half were not. The second study examined qualitative information from women recently stalked (n = 62) by a violent partner. Results from both studies suggest that women who were stalked by a violent partner were significantly more susceptible to on-the-job harassment and problems. Also, women reported that stalking by a partner interfered in their work through on-the-job harassment, work disruption, and job performance problems. Implications for policy and research are discussed.  相似文献   
888.
It is a widely voiced notion that juvenile delinquency and victimization co-occur extensively in the youth population, in particular because delinquent youth engage in risky activities. But theory from the bullying and traumatic stress literatures suggests that there may be additional pathways by which delinquency and victimization are connected. This analysis looks for possible subtypes of delinquents and victims consistent with such pathways. Using the Developmental Victimization Survey, a national sample of 1,000 youth aged 10 to 17 were interviewed over the phone. Support emerges for three distinct types of delinquent-victims, who are termed bully-victims, delinquent sex/maltreatment- victims, and property delinquent-victims. There is also evidence for substantial groups of youth who are primarily delinquent but not seriously victimized, as well as youth who are primarily victimized but not delinquent.  相似文献   
889.
We have analysed 13 autosomal STR loci in four endogamous tribal populations from two eastern states (Orissa and Nagaland) of India. The Gadaba, Kuvi Khond and Lotha Naga populations have not been analysed for microsatellite genetic variation previously. The allele frequencies for all loci are within the range observed in the geographical region and racial background, though some alleles showed greater variation. Departures from the Hardy-Weinberg equilibrium were tested by three methods and two loci (THO1 and TPOX) showed significant departures for all measures in Gadaba and Lotha Naga populations. The exclusion probability and discrimination probability were high for all analysed loci in all populations. There is no evidence for association of alleles among the STR loci studied. This allele frequency information will be useful for forensic, paternity and population genetic studies.  相似文献   
890.
We have analyzed nine autosomal STR loci (D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, and D7S820) in 97 samples of enigmatic Andaman islanders including: 15 Great Andamanese, 46 Onge and 36 Nicobarese. Data was compared with the available data on Indian and South East Asian populations. Heterozygosity (H), power of discrimination (PD), probability exclusion (PE), typical paternity index (TPI), polymorphism information content (PIC), AMOVA and Arlequin analysis were carried out. Average heterozygosity observed was high and almost equal in all the populations. Similarly, PD, PE, TPI and PIC have been almost equal in all the populations.  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