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   258694篇
  免费   18554篇
  国内免费   1152篇
耳鼻咽喉   2875篇
儿科学   6712篇
妇产科学   4715篇
基础医学   33853篇
口腔科学   4755篇
临床医学   26040篇
内科学   55148篇
皮肤病学   3516篇
神经病学   24929篇
特种医学   8576篇
外国民族医学   13篇
外科学   39392篇
综合类   3523篇
一般理论   319篇
预防医学   22017篇
眼科学   6695篇
药学   17329篇
  6篇
中国医学   373篇
肿瘤学   17614篇
  2023年   1375篇
  2022年   2475篇
  2021年   5618篇
  2020年   3363篇
  2019年   5527篇
  2018年   6203篇
  2017年   4649篇
  2016年   5128篇
  2015年   6019篇
  2014年   8830篇
  2013年   12104篇
  2012年   18377篇
  2011年   19251篇
  2010年   10813篇
  2009年   9623篇
  2008年   16896篇
  2007年   17784篇
  2006年   17619篇
  2005年   17558篇
  2004年   16424篇
  2003年   15269篇
  2002年   14299篇
  2001年   2272篇
  2000年   1791篇
  1999年   2490篇
  1998年   3130篇
  1997年   2626篇
  1996年   2237篇
  1995年   2147篇
  1994年   1792篇
  1993年   1611篇
  1992年   1397篇
  1991年   1305篇
  1990年   1126篇
  1989年   1104篇
  1988年   1084篇
  1987年   1043篇
  1986年   1060篇
  1985年   1036篇
  1984年   1284篇
  1983年   1177篇
  1982年   1387篇
  1981年   1339篇
  1980年   1170篇
  1979年   753篇
  1978年   769篇
  1977年   663篇
  1976年   613篇
  1975年   489篇
  1974年   494篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
973.
974.
975.
976.
977.
978.
Many information systems have failed when deployed into complex health-care settings. We believe that one cause of these failures is the difficulty in systematically accounting for the collaborative and exception-filled nature of medical work. In this methodological review paper, we highlight research from the field of computer-supported cooperative work (CSCW) that could help biomedical informaticists recognize and design around the kinds of challenges that lead to unanticipated breakdowns and eventual abandonment of their systems. The field of CSCW studies how people collaborate with each other and the role that technology plays in this collaboration for a wide variety of organizational settings. Thus, biomedical informaticists could benefit from the lessons learned by CSCW researchers. In this paper, we provide a focused review of CSCW methods and ideas-we review aspects of the field that could be applied to improve the design and deployment of medical information systems. To make our discussion concrete, we use electronic medical record systems as an example medical information system, and present three specific principles from CSCW: accounting for incentive structures, understanding workflow, and incorporating awareness.  相似文献   
979.
Most models suggest that the cell of origin of papillary carcinoma is the mature thyroid follicular epithelial cell. In a recent study, p63 was detected in papillary carcinoma, Hashimoto's thyroiditis, and in squamoid aggregates and solid cell nests (SCNs), embryonic remnants found sporadically in the fully developed thyroid. In the present study, the relationship between solid cell nests and papillary carcinoma was investigated further. Four-micrometer sections from 88 routinely fixed and processed archival thyroidectomy specimens were pretreated with citric acid pH 6.0 for antigen retrieval, then incubated overnight with anti-p63 monoclonal antibody 4A4. Slides were stained with a streptavidin-biotin kit and diaminobenzidine as chromogen and were counterstained with hematoxylin. Squamoid aggregates or SCNs were noted in 21 specimens. Several morphologic variants of SCNs were found, all of which displayed p63 positivity. These included undifferentiated SCNs and those displaying commitment toward squamoid and ciliated glandular differentiation. Small, morphologically inconspicuous aggregates of p63-positive cells were commonly found in Hashimoto's thyroiditis. Commitment of p63-positive undifferentiated cells toward thyroid follicular epithelial differentiation was occasionally noted. One SCN variant, also associated with Hashimoto's thyroiditis, was a floretlike arrangement of p63-positive cells with fusiform nuclei. p63 staining was strong and uniform in some SCNs, but in other SCNs it was compartmentalized and homologous to stem cell-staining patterns in normal squamous or bronchial epithelia. Stem cell-like staining, associated with compartmentalized p63 staining or p63-positive undifferentiated cells, was noted in 7 of 27 papillary carcinomas. p63 immunostaining is a highly sensitive means of detecting SCNs. p63 expression patterns in SCNs and a subset of papillary carcinomas are closely homologous to stem cell-associated p63 staining patterns that have been described elsewhere in squamous and bronchial epithelia. We propose a stem-cell-associated model of papillary carcinoma oncogenesis that suggests that (1) p63-positive embryonal remnants rather than mature follicular cells are the cells of origin of a subset of papillary carcinomas; (2) these p63-positive cells are pluripotent and may stay undifferentiated or undergo benign squamoid or glandular maturation, may undergo thyroid follicular epithelial differentiation, may undergo oncogenic change leading to papillary carcinoma, or may trigger an immune reaction, resulting in lymphoid infiltration and Hashimoto's thyroiditis; and (3) Hashimoto's thyroiditis and papillary carcinoma may therefore be linked etiologically, because both disorders may be initiated by the same population of pluripotent p63-positive embryonal stem cell remnants.  相似文献   
980.
The genetic diversity of enteric viruses co-circulating in a cohort of patients with viral gastroenteritis in a large tertiary paediatric hospital in London, UK, was determined. Multiple strains of noroviruses (NV), sapoviruses (SV) and astroviruses (HAsV) were detected in these patients, indicating the likelihood of multiple introductions from different sources, possible sub-clinical infections and simultaneous infection with different viruses in immunocompromised and other patients. Routine screening of immunocompromised patients and infection control procedures are important to prevent nosocomial infection.  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