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   64169篇
  免费   5395篇
  国内免费   2703篇
耳鼻咽喉   315篇
儿科学   1526篇
妇产科学   1419篇
基础医学   7728篇
口腔科学   999篇
临床医学   8902篇
内科学   11085篇
皮肤病学   795篇
神经病学   4681篇
特种医学   1692篇
外国民族医学   23篇
外科学   6295篇
综合类   6153篇
现状与发展   12篇
一般理论   31篇
预防医学   5999篇
眼科学   1337篇
药学   5594篇
  15篇
中国医学   1930篇
肿瘤学   5736篇
  2024年   126篇
  2023年   747篇
  2022年   1555篇
  2021年   2084篇
  2020年   1717篇
  2019年   1773篇
  2018年   1927篇
  2017年   1705篇
  2016年   1684篇
  2015年   2368篇
  2014年   2915篇
  2013年   3147篇
  2012年   4861篇
  2011年   4968篇
  2010年   2935篇
  2009年   2507篇
  2008年   3739篇
  2007年   3918篇
  2006年   3621篇
  2005年   3762篇
  2004年   3037篇
  2003年   2819篇
  2002年   2534篇
  2001年   1108篇
  2000年   1191篇
  1999年   1273篇
  1998年   935篇
  1997年   904篇
  1996年   701篇
  1995年   682篇
  1994年   611篇
  1993年   448篇
  1992年   425篇
  1991年   421篇
  1990年   398篇
  1989年   347篇
  1988年   291篇
  1987年   283篇
  1986年   254篇
  1985年   225篇
  1984年   197篇
  1983年   148篇
  1982年   124篇
  1981年   120篇
  1980年   99篇
  1979年   82篇
  1978年   80篇
  1977年   60篇
  1976年   40篇
  1975年   44篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
OBJECTIVES: To critically review and integrate, from a developmental perspective, recent magnetic resonance imaging (MRI) studies of 4 childhood psychiatric disorders: schizophrenia, bipolar disorder (BD), attention-deficit hyperactivity disorder (ADHD), and major depressive disorder (MDD). METHOD: We reviewed published reports in refereed journals. We briefly describe the major findings with respect to the brain morphometry, chemistry, and function of children with psychiatric disorders and synthesize the reports in a summary to update clinicians. RESULTS: Some cortical grey matter abnormalities associated with schizophrenia appear to predate the onset of frank psychosis and continue to advance after the onset of psychosis, at least in more severe cases. Pediatric BD is associated with abnormalities in a circuit, thought to be involved in mood regulation, that encompasses the amygdala, striatum, and ventral PFC. Frontostriatal abnormalities are reported consistently in ADHD, potentially reflecting abnormalities in the development of cognitive control. Children with MDD show prefrontal cortical alterations that may differ in familial and nonfamilial subtypes of MDD. CONCLUSIONS: Results from neuroimaging studies of childhood psychopathology reveal abnormalities in the developmental trajectories observed in healthy children. Although MRI has increased our understanding of the pathophysiology of these disorders, routine neuroimaging for children with severe emotional disturbances is not indicated for diagnostic purposes.  相似文献   
92.
浅谈健康教育中的护理风险管理   总被引:3,自引:0,他引:3  
沈佩娟 《护理研究》2006,20(3):729-730
健康教育作为临床护理中的重要内容,对病人的疾病转归有重要作用。而任何医疗护理行为都是具有超过各种服务之上的高科技行为的组合活动,具有高风险性,健康教育同样存在一定的风险性。所以,我们应提高风险意识,加强风险管理,将风险降低至最低限度。  相似文献   
93.
94.
95.
96.
97.
98.
为探讨药效法估测的效应消除半衰期和效量法估测的表观半衰期对合理制订给药方案的意义和作用,以桂枝汤解热和抗炎的药物动力学实验中所得的相应参数值设计了给药方案,观察了它们在提高药效上的作用。结果表明在给药总剂量相等、首次给药同时开始的情况下,以半衰期设计的给药方案组的药效均明显高于习惯的一次给药组;而以效应消除半衰期设计给药方案组药效增强率又高于以表观半衰期设计的方案组。提示效应消除半衰期比表观半衰期似更有实践意义。  相似文献   
99.
Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai, China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fungi. They were also examined for aflatoxin, endotoxin, and potential to stimulate production of human interleukin 1 beta (IL-1 beta) and to consume complement. The concentrations of total microorganisms were consistently greater than 10(7) CFU/g and ranged from 10(7) to 10(9) CFU/g. In general, the level of microbial contamination was greater in the hay dust samples than in the rice dust samples, with bacteria being the most numerous microorganisms observed followed by molds, thermophilic actinomycetes, and yeasts. The predominant fungi were species of Aspergillus, Cladosporium, Penicillium, Trichosporon, and Cryptococcus. No significant levels of aflatoxin were observed and the isolates of A. flavus examined lack significant aflatoxigenic potential. The levels of microorganisms in these samples, the types of organisms found, and the inflammatory mediators such as endotoxin suggest that workers exposed to these dusts may be at risk for respiratory illness.  相似文献   
100.
We investigated the role of metabolism in muscle fatigue during voluntary exercise in persons with mild multiple sclerosis (MS). Six MS and 8 healthy control subjects performed intermittent, progressive, isometric contractions of the ankle dorsiflexors, during which we measured maximum voluntary force (MVC), inorganic phosphate (Pi), phosphocreatine (PCr), and pH. During exercise. MVC fell sooner in MS, but by the end of exercise the relative decrease in MVC was similar in both groups. In contrast, at the end of exercise Pi/PCr increased to 1.86 ± 0.22 in controls but to only 0.66 ± 0.04 in MS (P < 0.01); likewise, pH was 6.75±0.04 in controls and unchanged (7.06 ± 0.04) in MS (P <0.01). The smaller metabolic change at the same relative exercise intensity suggests a failure of muscle activation that is present even in mild MS. Neurophsyiologic measures of activation indicated some central activation failure and no neuromuscular junction impairment in MS, and suggested that activation failure beyond the muscle membrane(excitation–contraction coupling) may be important in MS. We conclude that metabolic factors do not play a significant role in the development of muscle fatigue during voluntary exercise in mild MS. © 1994 John Wiley & Sons, Inc.  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