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   12134篇
  免费   1253篇
各国政治   456篇
工人农民   403篇
世界政治   892篇
外交国际关系   311篇
法律   9164篇
中国共产党   1篇
中国政治   87篇
政治理论   1995篇
综合类   78篇
  2020年   340篇
  2019年   353篇
  2018年   398篇
  2017年   460篇
  2016年   473篇
  2015年   431篇
  2014年   425篇
  2013年   1263篇
  2012年   276篇
  2011年   369篇
  2010年   541篇
  2009年   496篇
  2008年   289篇
  2007年   257篇
  2006年   362篇
  2005年   255篇
  2004年   247篇
  2003年   233篇
  2002年   208篇
  2001年   443篇
  2000年   360篇
  1999年   305篇
  1998年   156篇
  1997年   140篇
  1996年   111篇
  1995年   142篇
  1994年   150篇
  1993年   126篇
  1992年   221篇
  1991年   245篇
  1990年   228篇
  1989年   240篇
  1988年   215篇
  1987年   181篇
  1986年   211篇
  1985年   231篇
  1984年   225篇
  1983年   203篇
  1982年   153篇
  1981年   139篇
  1980年   134篇
  1979年   157篇
  1978年   95篇
  1977年   85篇
  1976年   70篇
  1975年   72篇
  1974年   81篇
  1973年   68篇
  1972年   57篇
  1971年   59篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
301.
302.
303.
304.
305.
306.
ABSTRACT

Assessing the risk for animal cruelty is imperative, yet understudied and problematic due to the sensitivity of the topic. Early prevention is critical, yet very little research examines cruelty when it first appears in childhood. The aim of this study was to explore children’s attitudes towards types of animal cruelty, to investigate potential demographic differences, and to examine potential associations between acceptance of cruelty and cognitive and affective factors that place children ‘at-risk’ for cruelty perpetration. Questionnaire data was collected from 1127 children in schools. The results indicate that cruelty attitudes are predicted by some demographic variables such as urban living, being male, younger age and not having pets, but depend on the type of animal cruelty. Acceptance of cruelty predicted low compassion and low reported humane behaviour towards animals. Acceptance of cruelty was predicted by negative attitudes towards animals, lower beliefs in animal minds and low attachment to pets, signifying the importance of targeting such variables in future prevention programmes. This study is an original contribution to research into childhood animal cruelty in the general population, with implications for designing and implementing early prevention programmes that tackle problematic attitudes to cruelty.  相似文献   
307.
High‐throughput sequencing (HTS) of large panels of single nucleotide polymorphisms (SNPs) provides an alternative or complimentary approach to short tandem repeats (STRs) panels for the analysis of complex DNA mixture forensic samples. For STRs, methods to estimate individual contribution concentrations compare capillary electrophoresis peak heights, peak areas, or HTS allele read counts within a mixture. This article introduces three approaches (mean, median, and slope methods) for estimating individual DNA contributions to forensic mixtures for HTS/massively parallel sequencing (MPS) SNP panels. For SNPs, the major:minor allele ratios or counts, unique to each contributor, were compared to estimate contributor proportion within the mixture using the mean, median, and slope intercept for these alleles. The estimates for these three methods were typically within 5% of planned experimental contributions for defined mixtures.  相似文献   
308.
309.
Fluoxetine is a selective serotonin reuptake inhibitor, commonly used for the treatment of a variety of psychopathological conditions. As such, fluoxetine may be expected to appear in clinical and forensic cases. Dermestes maculatus De Geer (Coleoptera: Dermestidae) has been recognized as a relevant component of the insect fauna associated with decomposing human and animal remains. Experiments were conducted to study the effect of fluoxetine on developing D. maculatus using two‐drug administration models: a non‐living animal model (pork muscle) and a living one (Sus scrofa L. pigs). We assessed the duration of immature stages and total life cycle, as well as morphological parameters (body length, cephalic width, and weight). The effect of fluoxetine was studied at an overdose concentration: In the non‐living animal model the drug was mixed with macerated pork muscle (2000 mg/kg) and in the living animal model, pigs were given the drug orally (833 mg/kg). A control was used for each model. Daily observations were performed from the beginning to the end of the experiments. GC‐MS was used for drug detection and quantification. There were no statistically significant differences in the duration of immature stages, life cycle, larval mortality, morphological parameters, or sex ratio, between treatment and control, regardless of the drug administration model. Given that fluoxetine had no detectable effect on the development of D. maculatus, detection of this drug in forensic situations would not compromise the accuracy of PMI estimations.  相似文献   
310.
Gordon Welchman was a Cambridge mathematician and one of the key figures working at Bletchley Park (BP) during World War Two. In 1974, he decided to write his own memoir following the publication of other books on the subject. His book ‘The Hut Six Story’ was published in both the US and UK in early 1982 and was the first to include technical details about the BP operation. Pressure on his publishers from the NSA and GCHQ ultimately resulted in the book being withdrawn from their lists. On 14 May 1982, he wrote this previously unpublished paper, explaining his motives.  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