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   1832354篇
  免费   136093篇
  国内免费   2771篇
耳鼻咽喉   24128篇
儿科学   60422篇
妇产科学   49402篇
基础医学   276166篇
口腔科学   51618篇
临床医学   169083篇
内科学   354066篇
皮肤病学   40618篇
神经病学   141706篇
特种医学   67871篇
外国民族医学   335篇
外科学   264252篇
综合类   38491篇
现状与发展   4篇
一般理论   692篇
预防医学   146623篇
眼科学   41835篇
药学   136687篇
  9篇
中国医学   4146篇
肿瘤学   103064篇
  2018年   19684篇
  2017年   15106篇
  2016年   16588篇
  2015年   19028篇
  2014年   26154篇
  2013年   39882篇
  2012年   53660篇
  2011年   56977篇
  2010年   33214篇
  2009年   31791篇
  2008年   53655篇
  2007年   57467篇
  2006年   57457篇
  2005年   55449篇
  2004年   53556篇
  2003年   51176篇
  2002年   49605篇
  2001年   84560篇
  2000年   86179篇
  1999年   72174篇
  1998年   19870篇
  1997年   17612篇
  1996年   18175篇
  1995年   17268篇
  1994年   16046篇
  1993年   14943篇
  1992年   56703篇
  1991年   56092篇
  1990年   54351篇
  1989年   53126篇
  1988年   49014篇
  1987年   47842篇
  1986年   45624篇
  1985年   42959篇
  1984年   32469篇
  1983年   28032篇
  1982年   16218篇
  1981年   14651篇
  1979年   30410篇
  1978年   22026篇
  1977年   18477篇
  1976年   17400篇
  1975年   18885篇
  1974年   22617篇
  1973年   22193篇
  1972年   20886篇
  1971年   19584篇
  1970年   18620篇
  1969年   17414篇
  1968年   16158篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
First described in 1955 in New Jersey, epizootic haemorrhagic disease (EHD) causes a severe clinical disease in wild and domestic ruminants worldwide. Epizootic haemorrhagic disease outbreaks occur in deer populations each year from summer to late autumn. The etiological agent is EHD virus (EHDV) which is a double‐stranded segmented icosahedral RNA virus. EHD virus utilizes point mutations and reassortment strategies to maintain viral fitness during infection. In 2018, EHDV serotype 2 was predominantly detected in deer in Illinois. Whole genome sequencing was conducted for two 2018 EHDV2 isolates (IL41747 and IL42218) and the sequence analyses indicated that IL42218 was a reassortant between different serotypes whereas IL41747 was a genetically stable strain. Our data suggest that multiple strains contribute to outbreaks each year.  相似文献   
163.
Accurate diagnosis and recognition of predisposing factors has been shown to be challenging in lower limb cellulitis (LLC). Assessment of 1746 consecutive patients with cellulitis presenting to a UK university hospital showed increasing overdiagnosis, with only 31.9% of patients referred during the period 2015–2018 having the diagnosis of LLC confirmed. Recognition of at least one predisposing factor increased from 61% to 89% following introduction of more specific screening questions. This identified a need for better primary care dermatology education and the benefit of a proforma with specific screening questions for reversible predisposing factors for LLC.  相似文献   
164.
Background: Egyptian street youth use substances including tobacco, illicit drugs, and pharmaceutical drugs. To understand the circumstances, including adverse childhood experiences, that place adolescents at risk for engaging in substance use, we conducted in-depth interviews among a sample of Egyptian street children. Methods: From youth residing at or attending Caritas, a non-profit organization, which provides shelter and education to street youth, seven girls and twelve boys, aged 12–18 years, participated in open-ended, in-depth interviews. Results: Eight out of the 19 participants reported family history (early exposure) to substance use; and seven of them were initiated by either a family member (sibling), friend or coworker. Most of the participants reported a history of conflict with or abuse (verbal or physical) by their parents or siblings, or stressful situations at home; they used substance(s) to alleviate their stress. Few attended school, and some were forced to work and help their family. Conclusions: Among Egyptian youth, adverse childhood experiences, such as poverty, child abuse, and family substance use, challenge somewhat susceptible youths and lead them to the path of substance use and addiction. Prevention intervention should be multifaceted, culturally adaptable, and primarily targeting the social environment during childhood.  相似文献   
165.
166.
167.
168.
169.
170.
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