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   232132篇
  免费   6134篇
  国内免费   3555篇
耳鼻咽喉   1682篇
儿科学   7292篇
妇产科学   3537篇
基础医学   23294篇
口腔科学   2487篇
临床医学   19136篇
内科学   39919篇
皮肤病学   1412篇
神经病学   19646篇
特种医学   11533篇
外国民族医学   19篇
外科学   34874篇
综合类   11147篇
现状与发展   14篇
一般理论   8篇
预防医学   21625篇
眼科学   4160篇
药学   15352篇
  52篇
中国医学   3489篇
肿瘤学   21143篇
  2024年   161篇
  2023年   800篇
  2022年   2036篇
  2021年   2820篇
  2020年   2054篇
  2019年   1848篇
  2018年   23647篇
  2017年   18987篇
  2016年   21259篇
  2015年   3651篇
  2014年   4083篇
  2013年   4045篇
  2012年   11551篇
  2011年   25787篇
  2010年   22215篇
  2009年   14154篇
  2008年   22699篇
  2007年   24901篇
  2006年   3474篇
  2005年   5045篇
  2004年   5445篇
  2003年   6516篇
  2002年   4312篇
  2001年   1684篇
  2000年   1531篇
  1999年   1192篇
  1998年   793篇
  1997年   780篇
  1996年   472篇
  1995年   538篇
  1994年   408篇
  1993年   254篇
  1992年   333篇
  1991年   306篇
  1990年   306篇
  1989年   269篇
  1988年   176篇
  1987年   176篇
  1986年   158篇
  1985年   102篇
  1984年   64篇
  1983年   47篇
  1982年   59篇
  1980年   57篇
  1974年   31篇
  1969年   36篇
  1938年   60篇
  1934年   30篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Coronary flow reserve (CFR) has been used toassess coronary microcirculation and epicardial coro-nary stenoses[1— 3 ] . CFR is defined as the ratio ofcoronary flow under maximal coronary vasodilatationto coronary flow under resting conditions[4 ] .Whenthe cross- sectional area of epicardial coronary arteriesis constant,coronary flow velocity (CFV) ratios areequal to volume flow ratios.The most common method used clinically formeasuring CFVR is intracoronary Doppler flow(ICD) analysis re…  相似文献   
12.
OBJECTIVE: To understand the role of nasal mucous epithelial cells to hypoxia in early stage of nasal polyps(NP) formation. METHODS: Epithelial cells of NP and inferior turbinate (IT) were cultured without serum under normal oxygen and hypoxia, and stimulus of inflammatory cytokines. Erythropoietin (EPO) was regarded as hypoxia mark, and expression of vascular endothelial growth factor(VEGF) mRNA and protein derived from epithelial cells were detected respectively by in situ hybridization and ELISA. RESULTS: 1. Under hypoxia, EPO mRNA was expressed intensely in epithelial cells from NP and IT, and there was no significant difference between both of them. This result suggested that EPO might be regarded as a hypoxic mark. 2. The ability of producing VEGF mRNA increased with cytokines stimulation, especially under hypoxia. Protein level of VEGF from epithelial cells of NP and IT increased with cytokines stimulation, especially in hypoxia and was time-dependent. CONCLUSION: Epithelial cells actively produce vast VEGF under hypoxia. The VEGF induced by hypoxia of the mucosa in middle meatus is of importance in the formation of nasal polyps(NP) in early stage, which may be the major cause of NP formation in middle meatus.  相似文献   
13.
14.
Contemporary discourse contains numerous examples of use of the concept of culture by social and behavioral scientists. Simple reification, where the speaker makes culture into a thing capable of action exemplifies one usage in public discourse. Some quantitative social scientists attempt to characterize people’s cultural identities by means of a single categorical variable, which often “lumps” people into categories such as “Hispanic” or “Black” that in fact have numerous culturally bounded subcategories. Approaches that emphasize cultural process are preferable to those who attempt to categorize; more complex measures of acculturation help investigators to make convincing analyses of circumstances in which health disparities occur. Examples in which investigators make appropriate use of cultural characterizations demonstrate their utility in investigating health disparities in Haitian American women, injecting and noninjecting drug users, Hispanic youth, and adult Hispanics at risk of HIV infection. Focus on culture in the study of health disparities can identify entanglements between structural factors such as poverty and lack of education and cultural factors such as beliefs about health. Qualitative methods coupled with quantitative methods have great potential to improve investigators’ grasp of cultural nuance while capturing the distribution of qualitatively derived behaviors.  相似文献   
15.
16.
The specific characteristics of genetic data lead to ethical-legal conflicts in the framework of genetic diagnosis. Several international organisations, including UNESCO and the Council of Europe, have enacted rules referring to the use of genetic information. This paper discusses possible legal and ethical criteria that could be used in genetic testing.  相似文献   
17.
18.

Introduction  

This paper presents the results of a study on the psychometric properties of an authorized Spanish version of the McMaster Family Assessment Device, a self-report measure of family functioning.  相似文献   
19.
20.
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