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   2894263篇
  免费   233722篇
  国内免费   5501篇
耳鼻咽喉   42728篇
儿科学   88409篇
妇产科学   78408篇
基础医学   409349篇
口腔科学   84130篇
临床医学   262091篇
内科学   561241篇
皮肤病学   58811篇
神经病学   242993篇
特种医学   116000篇
外国民族医学   1042篇
外科学   440253篇
综合类   72561篇
现状与发展   3篇
一般理论   1168篇
预防医学   233793篇
眼科学   69455篇
药学   216181篇
  4篇
中国医学   5374篇
肿瘤学   149492篇
  2018年   28610篇
  2016年   24533篇
  2015年   27871篇
  2014年   40227篇
  2013年   61432篇
  2012年   82698篇
  2011年   87196篇
  2010年   51334篇
  2009年   49067篇
  2008年   82751篇
  2007年   88633篇
  2006年   89241篇
  2005年   87110篇
  2004年   84307篇
  2003年   81418篇
  2002年   80156篇
  2001年   130007篇
  2000年   134490篇
  1999年   113890篇
  1998年   33475篇
  1997年   30552篇
  1996年   30132篇
  1995年   29134篇
  1994年   27447篇
  1993年   25571篇
  1992年   93019篇
  1991年   89779篇
  1990年   86895篇
  1989年   83716篇
  1988年   78018篇
  1987年   77027篇
  1986年   72871篇
  1985年   69945篇
  1984年   53443篇
  1983年   45720篇
  1982年   28241篇
  1981年   25246篇
  1980年   23765篇
  1979年   51274篇
  1978年   36322篇
  1977年   30597篇
  1976年   28602篇
  1975年   30330篇
  1974年   37520篇
  1973年   35871篇
  1972年   33641篇
  1971年   31076篇
  1970年   29403篇
  1969年   27649篇
  1968年   25151篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
A 27-year-old man was admitted with high fever and shivers eleven days after returning from vacation in Indonesia. Physical examination, laboratory values, abdominal ultrasound, and chest x-ray were not conclusive. All blood cultures yielded growth of Salmonella enterica serovar Typhi, and typhoid fever was diagnosed. Subsequently, the patient developed septic shock and pulmonary edema.In this case report epidemiological, clinical, and therapeutic aspects of typhoid fever are discussed with special emphasis on criteria for severe typhoid fever, which is treated with additional glucocorticoids.  相似文献   
73.
74.
75.
76.
77.
78.
79.
To determine if impaired energy metabolism might contribute to some aspects of Alzheimer disease (AD), including the vulnerability of the CA1 region of the hippocampal formation and the altered cytoskeleton evident in neurofibrillary tangles, we examined the effects of metabolic poisons on neuronal damage and cytoskeletal disruption in the hippocampal formation. Intrahippocampal injection of 3-nitropropionic acid (3-NP) and malonic acid resulted in neuronal death, particularly in CA1. Cytoskeletal disruption included loss of dendritic MAP2, but sparing of axonal τ. MK-801 (a noncompetitive NMDA receptor antagonist) did not atenuate the lesions produced by intrahippocampal injection of malonate. MK-801, however, was effective against intrastriatal malonate. Acute systemic 3-NP resulted in neuronal damage and cytoskeletal disruption in the CA1 region of the hippocampal formation, including an extensive loss of MAP2 immuno-reactivity, but sparing of τ. The neuronal loss in CA1 was delayed as compared to striatum. Chronic intraventricular infusion of 3-NP produced a different pattern of neuronal damage. Loss of τ-1 immuno-reactivity was observed in CA3 and CA1 s. oriens, whereas MAP2 immunostaining was preserved. These results demonstrate that chronic and acute administration of metabolic inhibitors produce distinct patterns of neuronal damage and cytoskeletal disruption. The results further suggest a differential involvement of the NMDA receptor in malonate-induced neuronal damage in striatum as compared to the hippocampus. The pattern of neuronal damage and cytoskeletal disruption observed following acute metabolic impairment resembled some aspects of neurofibrillary pathology in AD, but did not result in τ hyperphosphorylation.  相似文献   
80.
AIM: Cardiovascular risk factors can be present in children and young adults. We previously found abnormal microvascular function in children who had glucose intolerance and insulin resistance. The aim of the present study was to investigate whether they also have abnormalities in left ventricular mass (LVM) and arterial stiffness. METHODS: We measured heart dimensions and LVM using echocardiography, and arterial stiffness using pulse wave analysis in 23 children with good glucose handling (postfeeding glucose: 3.9 to 5 mmol/L) and 21 with poor glucose handling (7.7 to 11.4 mmol/L). RESULTS: The time to pulse reflection was slightly shorter in the poorer glucose handlers (mean+/-SD: 143+/-10 vs 153+/-20 ms, P=0.04), suggestive of increased arterial stiffness. Also in this group, there were significant relationships between intraventricular septal thickness, blood pressure and body mass index, but not in the normal glucose handlers. CONCLUSIONS: We have found that normal children who are in the lowest quintile of glucose tolerance in comparison with their peers are exhibiting the first signs of arterial stiffening. In addition, we have seen the beginnings of a relationship between blood pressure, body mass index and left ventricular enlargement in this group. While these changes may not yet be clinically significant, their emergence might be further evidence of early predisposition to cardiovascular disease.  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