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   427篇
  免费   22篇
各国政治   24篇
工人农民   58篇
世界政治   38篇
外交国际关系   22篇
法律   207篇
中国政治   5篇
政治理论   90篇
综合类   5篇
  2023年   7篇
  2022年   2篇
  2021年   3篇
  2020年   6篇
  2019年   14篇
  2018年   21篇
  2017年   16篇
  2016年   15篇
  2015年   15篇
  2014年   11篇
  2013年   69篇
  2012年   18篇
  2011年   10篇
  2010年   12篇
  2009年   11篇
  2008年   22篇
  2007年   21篇
  2006年   15篇
  2005年   16篇
  2004年   12篇
  2003年   13篇
  2002年   8篇
  2001年   6篇
  2000年   4篇
  1999年   9篇
  1998年   5篇
  1997年   4篇
  1996年   11篇
  1995年   8篇
  1994年   3篇
  1993年   6篇
  1992年   5篇
  1991年   5篇
  1990年   8篇
  1989年   4篇
  1988年   10篇
  1987年   3篇
  1985年   2篇
  1984年   3篇
  1982年   1篇
  1981年   2篇
  1980年   3篇
  1979年   1篇
  1978年   3篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
  1973年   1篇
排序方式: 共有449条查询结果,搜索用时 62 毫秒
271.
Carrion‐breeding insects, such as flesh flies (Diptera: Sarcophagidae), can be used as evidence in forensic investigations. Despite their considerable forensic potential, their use has been limited because morphological species identification, at any life stage, is very challenging. This study investigated whether DNA could be extracted and cytochrome oxidase subunit I (COI) barcode sequences obtained for molecular identification of each immature life stage of the forensically important Australian flesh fly, Sarcophaga (Sarcorohdendorfia) impatiens (Walker). Genomic DNA extracts were prepared from all larval instars and puparia. Amplification of the barcoding region was successful from all extracts, but puparia amplicons were weak. All sequences were identified as S. impatiens with 99.95% confidence using the Barcoding of Life Database (BOLD). Importantly, crop removal was necessary to eliminate PCR inhibition for specimens from late second and early third instars. Similar results are expected for immatures of other carrion‐breeding species, enhancing the use of evidence from immature flies in forensic investigations.  相似文献   
272.
273.
Cyberbullying has been a difficult problem for policy makers and observers to define. For some, cyberbullying is understood as a public health problem, while others view it largely as an education issue, and still others see it as a justice problem. In Canada, while the definition of cyberbullying continues to evolve, a nascent approach assumes that it is similar to traditional face‐to‐face bullying with computer‐mediated communication as a new element. This definition is at odds with recent research on cyberbullying, which may have significant implications for policy makers seeking to design effective interventions.  相似文献   
274.
This study documents the policy framework that shapes First Nations' experience of relocating to access medical care. We analyzed policy documents and government websites, interviewed individuals who have experienced relocation, family members, healthcare providers, health administrators, and conducted two focus groups with government representatives. Federal and provincial program managers interpret policies, make decisions on eligibility, to extend or deny coverage. Decisions are shaped by shrinking budgets, fragmented program coverage, and jurisdictional confusion. Provider advocacy can help, but also perpetuate perceptions of arbitrariness and distrust. National policy renewal is required to redress this issue.  相似文献   
275.
276.
277.
278.
279.
280.
Journal of Youth and Adolescence - This study addressed the need for research examining impacts of the Coronavirus-19 (COVID) pandemic on Latinx adolescents’ adjustment. Survey data for a...  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