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   417191篇
  免费   24671篇
  国内免费   17696篇
耳鼻咽喉   3455篇
儿科学   9523篇
妇产科学   5221篇
基础医学   40593篇
口腔科学   5864篇
临床医学   44153篇
内科学   62125篇
皮肤病学   3223篇
神经病学   27303篇
特种医学   17899篇
外国民族医学   116篇
外科学   52872篇
综合类   51900篇
现状与发展   69篇
一般理论   22篇
预防医学   37229篇
眼科学   9007篇
药学   35114篇
  293篇
中国医学   18594篇
肿瘤学   34983篇
  2024年   916篇
  2023年   3636篇
  2022年   9770篇
  2021年   12294篇
  2020年   9730篇
  2019年   7596篇
  2018年   29412篇
  2017年   24699篇
  2016年   26431篇
  2015年   12461篇
  2014年   14969篇
  2013年   14593篇
  2012年   26890篇
  2011年   42658篇
  2010年   34145篇
  2009年   24255篇
  2008年   34245篇
  2007年   35880篇
  2006年   14471篇
  2005年   14646篇
  2004年   11671篇
  2003年   12195篇
  2002年   9001篇
  2001年   5533篇
  2000年   5018篇
  1999年   4221篇
  1998年   2729篇
  1997年   2625篇
  1996年   2009篇
  1995年   1869篇
  1994年   1505篇
  1993年   950篇
  1992年   1031篇
  1991年   899篇
  1990年   870篇
  1989年   712篇
  1988年   584篇
  1987年   514篇
  1986年   385篇
  1985年   313篇
  1984年   155篇
  1983年   114篇
  1982年   96篇
  1981年   72篇
  1980年   83篇
  1979年   64篇
  1974年   41篇
  1938年   60篇
  1932年   59篇
  1930年   47篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
11.
12.
Adrenergic signalling between rat taste receptor cells   总被引:2,自引:0,他引:2  
In taste buds, synaptic transmission is traditionally thought to occur from taste receptor cells to the afferent nerve. This communication reports the novel observation that taste receptor cells respond to adrenergic stimulation. Noradrenaline application inhibited outward potassium currents in a dose-dependent manner. This inhibition was mimicked by the β agonist isoproterenol and blocked by the β antagonist propranolol. The α agonists clonidine and phenylephrine both inhibited the potassium currents and elevated intracellular calcium levels. Inwardly rectifying potassium currents were unaffected by adrenergic stimulation. Experiments using the RT-PCR technique demonstrate that lingual epithelium expresses multiple α (α1a, α1b, α1c, α1d, α2a, α2b, α2c) and β (β1, β2) subtypes of adrenergic receptors, and immunocytochemistry localized noradrenaline to a subset of taste receptor cells. Collectively, these data imply strongly that adrenergic transmission within the taste bud may play a paracrine role in taste physiology.  相似文献   
13.
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   
14.
15.
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   
16.
17.
阳蔚 《护理研究》2006,20(5):1307-1307
临床工作中,医务人员在分离注射器、输液器针头时,常用止血钳、纱布或直接用手分离,这些方法易被针头刺伤。在许多医院使用自动针头毁形器。现介绍一种低成本、易制作及安装的简易针头拔出器。  相似文献   
18.
19.
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference.  相似文献   
20.
X Dong  M He  X Song  B Lu  Y Yang  S Zhang  N Zhao  L Zhou  Y Li  X Zhu  R Hu 《Diabetic medicine》2007,24(12):1482-1486
AIMS: Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks. METHODS: A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared. RESULTS: The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks. CONCLUSIONS: These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks.  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