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   2571385篇
  免费   200159篇
  国内免费   4859篇
耳鼻咽喉   37364篇
儿科学   80164篇
妇产科学   68853篇
基础医学   359962篇
口腔科学   74047篇
临床医学   231002篇
内科学   504964篇
皮肤病学   53538篇
神经病学   213283篇
特种医学   105013篇
外国民族医学   962篇
外科学   388182篇
综合类   57502篇
现状与发展   1篇
一般理论   997篇
预防医学   209239篇
眼科学   59570篇
药学   191141篇
  6篇
中国医学   4867篇
肿瘤学   135746篇
  2018年   29409篇
  2017年   23384篇
  2016年   24442篇
  2015年   28467篇
  2014年   38977篇
  2013年   56384篇
  2012年   80472篇
  2011年   80376篇
  2010年   46588篇
  2009年   45790篇
  2008年   73285篇
  2007年   78193篇
  2006年   79060篇
  2005年   83817篇
  2004年   82240篇
  2003年   75835篇
  2002年   70734篇
  2001年   115533篇
  2000年   118164篇
  1999年   102243篇
  1998年   28508篇
  1997年   25981篇
  1996年   25843篇
  1995年   25003篇
  1994年   23489篇
  1993年   21829篇
  1992年   83822篇
  1991年   81217篇
  1990年   78669篇
  1989年   75673篇
  1988年   70350篇
  1987年   69079篇
  1986年   65608篇
  1985年   62176篇
  1984年   46842篇
  1983年   39785篇
  1982年   23659篇
  1981年   20961篇
  1979年   44166篇
  1978年   30798篇
  1977年   25729篇
  1976年   24082篇
  1975年   25964篇
  1974年   32140篇
  1973年   30220篇
  1972年   28482篇
  1971年   26407篇
  1970年   24908篇
  1969年   23146篇
  1968年   21009篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
103.
Pancreatic panniculitis is an uncommon condition that can occur in association with pancreatic disease. We present a case of pancreatic panniculitis in a female pancreas-kidney transplant recipient 5 months post-transplant. The patient was on standard immunosuppressive medications and had acute rejection of her renal allograft. The diagnosis of allograft pancreatitis and rejection presenting with pancreatic panniculitis was supported clinically, histopathologically and by laboratory and imaging data. This is the fourth case of pancreatic panniculitis occurring in a transplant recipient and the first in a simultaneous pancreas-kidney transplant recipient. It is also the first case associated with allograft rejection. Clinicians should be aware that pancreatic panniculitis may be a manifestation of underlying allograft pancreatic disease.  相似文献   
104.
The purpose of this study is to determine the role of liver biopsy and outcome of patients undergoing donor evaluation for adult-to-adult right hepatic lobe living donor liver transplantation (LDLT). Records of patients presenting for a comprehensive donor evaluation between 1997 and February 2005 were reviewed. Liver biopsy was performed only in patients with risk factors for abnormal histology. Two hundred and sixty patients underwent a comprehensive donor evaluation and 116 of 260 (45%) were suitable for donation, 14 of 260 (5.4%) did not complete evaluation and 130 of 260 (50%) were rejected. Four patients underwent unsuccessful hepatectomy surgery due to discovery of intraoperative abnormalities. Between 1997 and 2001, the acceptance rate of donor candidates (63%) was higher than 2002-2005 (36%), p < 0.0001. Sixty-six of the 150 eligible patients (44%) fulfilled criteria for liver biopsy and 28 of 66 (42%) had an abnormal finding. Less than half of the patients undergoing donor evaluation were suitable donors and the donor acceptance rate has declined over time. A large proportion of the patients undergoing liver biopsy have abnormal findings. Our evaluation process failed to identify 4 of 103 who had aborted donor surgeries.  相似文献   
105.
We previously reported poorer survival among non-Hispanic blacks and Hispanics with idiopathic pulmonary fibrosis (IPF) compared to non-Hispanic whites at our center. In the current study, we hypothesized that these disparities would exist in a nationwide cohort of wait-listed patients with IPF. We performed a retrospective cohort study of 2635 patients with IPF listed for lung transplantation between 1995 and 2003 at 94 transplant centers in the United States. The age-adjusted mortality rate was higher among non-Hispanic blacks [hazard ratio (HR) = 1.24, 95% confidence interval (CI) 1.06-1.45, p = 0.009] and Hispanics (HR = 1.29, 95% CI 1.06-1.56, p = 0.01) compared to non-Hispanic whites. These findings persisted after adjustment for transplantation, medical comorbidities and socioeconomic status. Worse lung function at the time of listing appeared to explain some of these differences (HR for non-Hispanic blacks after adjustment for forced vital capacity percent predicted = 1.16, 95% CI 0.98-1.36, p = 0.09; HR for Hispanics = 1.21, 95% CI 0.99-1.48, p = 0.056). In summary, black and Hispanic patients with IPF have worse survival than whites after listing for lung transplant.  相似文献   
106.
Summary  We present the third case of Niemann–Pick disease type C without neurological symptoms. The patient was a 53-year-old woman without significant prior health problems who died of acute pulmonary embolism. Autopsy findings of hepatosplenomegaly, lymphadenopathy and ceroid-rich foam cells raised the suspicion of the visceral form of acid sphingomyelinase deficiency (Niemann–Pick disease type B; NPB) or a much rarer disorder, variant adult visceral form of Niemann–Pick disease type C (NPC). To verify the histopathological findings, SMPD1, NPC1 and NPC2 genes were analysed. Two novel sequence variants, c.1997G>A (S666N) and c.2882A>G (N961S) were detected in the NPC1 gene. No pathogenic sequence variants were found either in the SMPD1 gene mutated in NPB or in NPC2 gene. The pathogenicity of both NPC1 variants was supported by their location in regions important for the protein function. Both variations were not found in more than 300 control alleles. Identified sequence variations confirm the diagnosis of the extremely rare adult visceral form of Niemann–Pick disease type C, which is otherwise dominated by neurovisceral symptoms. Although only three patients have been reported, this (most probably underdiagnosed) form of NPC should be considered in differential diagnosis of isolated hepatosplenomegaly with foam cells in adulthood. Electronic supplementary material  Supplementary material is available for this article at  相似文献   
107.
We describe the simple adaptation of a standard fluorescent microscope for illumination using a 'Royal Blue' Luxeon light emitting diode (LED) and demonstrate that this form of illumination is suitable for the detection of auramine O stained Mycobacterium spp. The low cost, low power consumption, safety and reliability of LEDs makes them attractive alternatives to mercury vapour lamps.  相似文献   
108.
109.
OBJECTIVE: Gelastic seizures are a frequent and well established manifestation of the epilepsy associated with hypothalamic hamartomas. The scalp EEG recordings very seldom demonstrate clear spike activity and the information about the ictal epilepsy dynamics is limited. In this work, we try to isolate epileptic rhythms in gelastic seizures and study their generators. METHODS: We extracted rhythmic activity from EEG scalp recordings of gelastic seizures using decomposition in independent components (ICA) in three patients, two with hypothalamic hamartomas and one with no hypothalamic lesion. Time analysis of these rhythms and inverse source analysis was done to recover their foci of origin and temporal dynamics. RESULTS: In the two patients with hypothalamic hamartomas consistent ictal delta (2-3 Hz) rhythms were present, with subcortical generators in both and a superficial one in a single patient. The latter pattern was observed in the patient with no hypothalamic hamartoma visible in MRI. The deep generators activated earlier than the superficial ones, suggesting a consistent sub-cortical origin of the rhythmical activity. CONCLUSIONS: Our data is compatible with early and brief epileptic generators in deep sub-cortical regions and more superficial ones activating later. SIGNIFICANCE: Gelastic seizures express rhythms on scalp EEG compatible with epileptic activity originating in sub-cortical generators and secondarily involving cortical ones.  相似文献   
110.
Aggressive behavior linked to corticotropin-reactive autoantibodies.   总被引:3,自引:0,他引:3  
BACKGROUND: Altered stress response is characteristic for subjects with abnormal aggressive and antisocial behavior, but the underlying biological mechanisms are unclear. We hypothesized that autoantibodies (autoAbs) directed against several stress-related neurohormones may exist in aggressive subjects. METHODS: Using enzyme-linked immunosorbent assay, we studied whether autoAbs directed against corticotropin (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), oxytocin, and vasopressin are present in serum of male subjects with conduct disorder and prisoners with history of violence. Healthy blood donors served as control subjects. RESULTS: Both conduct disorder and prisoners groups displayed strongly increased levels of ACTH-reactive immunoglobulin G (IgG) and immunoglobulin M (IgM) autoAbs compared with control subjects. Levels of oxytocin-reactive IgM autoAbs were slightly increased in both groups of aggressive subjects, whereas levels of vasopressin-reactive IgG and IgM autoAbs were lower only in conduct disorder. No differences in the levels of alpha-MSH-reactive autoAbs were found between aggressive and control subjects. CONCLUSIONS: High levels of ACTH-reactive autoAbs as well as altered levels of oxytocin- and vasopressin-reactive autoAbs found in aggressive subjects may interfere with the neuroendocrine mechanisms of stress and motivated behavior. Our data suggest a new biological mechanism of human aggressive behavior that involves autoAbs directed against several stress-related neurohormones.  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