全文获取类型
收费全文 | 6228篇 |
免费 | 227篇 |
专业分类
各国政治 | 433篇 |
工人农民 | 181篇 |
世界政治 | 634篇 |
外交国际关系 | 450篇 |
法律 | 2615篇 |
中国政治 | 50篇 |
政治理论 | 2021篇 |
综合类 | 71篇 |
出版年
2023年 | 42篇 |
2022年 | 30篇 |
2021年 | 56篇 |
2020年 | 108篇 |
2019年 | 156篇 |
2018年 | 170篇 |
2017年 | 203篇 |
2016年 | 204篇 |
2015年 | 120篇 |
2014年 | 178篇 |
2013年 | 1048篇 |
2012年 | 179篇 |
2011年 | 182篇 |
2010年 | 177篇 |
2009年 | 185篇 |
2008年 | 164篇 |
2007年 | 222篇 |
2006年 | 197篇 |
2005年 | 229篇 |
2004年 | 233篇 |
2003年 | 210篇 |
2002年 | 226篇 |
2001年 | 120篇 |
2000年 | 116篇 |
1999年 | 97篇 |
1998年 | 90篇 |
1997年 | 94篇 |
1996年 | 90篇 |
1995年 | 92篇 |
1994年 | 93篇 |
1993年 | 79篇 |
1992年 | 84篇 |
1991年 | 91篇 |
1990年 | 62篇 |
1989年 | 65篇 |
1988年 | 65篇 |
1987年 | 63篇 |
1986年 | 68篇 |
1985年 | 62篇 |
1984年 | 53篇 |
1983年 | 62篇 |
1982年 | 48篇 |
1981年 | 55篇 |
1980年 | 38篇 |
1979年 | 37篇 |
1978年 | 32篇 |
1977年 | 33篇 |
1976年 | 30篇 |
1974年 | 15篇 |
1967年 | 14篇 |
排序方式: 共有6455条查询结果,搜索用时 0 毫秒
831.
Given the DNA profiles of two individuals and one parent (say the mother) of each, we present likelihood ratios (LRs) comparing the hypothesis that they have the same father with the hypothesis of unrelated fathers. If the individuals have the same mother, the problem is to distinguish full- from half-siblings, otherwise we are comparing a half-sibling relationship with unrelated. We simulate STR profiles at up to 60 loci, based on allele proportions observed at 15 loci in three populations, and use them to approximate misclassification rates both for binary classification (e.g. "half-sib" versus "unrelated"), and when a third "cannot say" category is included. We find that reliable inferences in the absence of the mothers' profiles require many more STR loci than the 10-25 loci that are currently routinely available. However, profiling the two mothers conveys more discriminatory power than profiling the same number of additional loci in the individuals themselves. Our likelihood ratio formulas include a theta (or Fst) adjustment to allow for the individuals concerned to have recent shared ancestry (coancestry), relative to the population from which the allele frequency database is drawn. We illustrate that using an appropriate value of theta can reduce the average misclassification rate. 相似文献
832.
833.
834.
835.
836.
837.
David L. Carter 《Journal of criminal justice》1985,13(6):487-500
This exploratory study examines relationships between the police and Hispanics in Texas. Specifically, data were collected on Hispanic evaluations of police performance, expectations of police performance, and overall satisfaction with the police. A sample of 500 Hispanics throughout the state of Texas were surveyed on their experienced and perceived relationships with three levels of police agencies: local (municipal) police, sheriff's officers, and the state's Department of Public Safety. Findings are reported based upon overall ratings of the police, victim-related data, and data from individuals who had any form of contact with the police. Significant findings show that any form of contact with the police appeared to lower the rating of police performance. This appears to be a product of the interaction between high public expectations and qualitatively poor police performance. Further findings indicate that an increase in the fear of crime among Hispanics lowered evaluations of local police. Similarly, victimization lowered the evaluation of local police, the county sheriff, and the Department of Public Safety. Hispanics also perceived that officers have a “bad attitude,” that the police need to patrol and investigate more, that response time should be improved, and that there should be less discrimination against Hispanics. These findings appear to be largely influenced by ineffective communication (both symbolic and linguistic) and cultural conflict. 相似文献
838.
839.
840.
Results are presented of a self-administered questionnaire completed by 201 youthful hallucinogen users. It was found that 55.5% of the population experienced at least one bad trip, although not one of these 111 subjects sought medical help. Investigation of the subject's family, drug-use pattern, mood, and environment revealed no clear-cut predisposing factors toward an adverse drug experience. While a significant correlation existed between a high level of cigarette consumption and a certain type of drug user, the number of different drugs used by the subjects was the only variable which positively correlated with the occurrence of a bad trip. Multiple stepwise regression indicated that over the period from 1965 to 1973 a change has taken place in the sample studied, such that today a young person introduced to hallucinogens is likely to take a greater number of drugs and is more likely to experience a bad trip than was his chronological conterpart of 1965.M.D. 1955 and Med. D.Sc. 1962: State University of New York. Presently Professor and Chairman, Department of Psychiatry, New York University. Current interests are in genetic-environmental interactions in the production of psychopathology.M.D. 1975: University of Connecticut. Presently first year resident in psychiatry, Yale Univeristy. Main research interests include potential biological correlates of psychological existential metatheory. 相似文献