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   1487篇
  免费   116篇
  国内免费   6篇
耳鼻咽喉   9篇
儿科学   37篇
妇产科学   41篇
基础医学   150篇
口腔科学   13篇
临床医学   164篇
内科学   397篇
皮肤病学   8篇
神经病学   80篇
特种医学   51篇
外科学   161篇
综合类   45篇
预防医学   101篇
眼科学   207篇
药学   87篇
肿瘤学   58篇
  2021年   14篇
  2020年   9篇
  2019年   18篇
  2018年   14篇
  2017年   19篇
  2016年   23篇
  2015年   20篇
  2014年   36篇
  2013年   53篇
  2012年   74篇
  2011年   72篇
  2010年   38篇
  2009年   28篇
  2008年   78篇
  2007年   79篇
  2006年   80篇
  2005年   65篇
  2004年   67篇
  2003年   62篇
  2002年   55篇
  2001年   48篇
  2000年   56篇
  1999年   48篇
  1998年   12篇
  1997年   11篇
  1996年   18篇
  1995年   12篇
  1994年   19篇
  1993年   11篇
  1992年   43篇
  1991年   46篇
  1990年   35篇
  1989年   28篇
  1988年   46篇
  1987年   30篇
  1986年   17篇
  1985年   24篇
  1984年   19篇
  1983年   14篇
  1982年   11篇
  1981年   12篇
  1980年   8篇
  1979年   11篇
  1978年   10篇
  1977年   11篇
  1976年   7篇
  1974年   13篇
  1973年   11篇
  1972年   10篇
  1971年   8篇
排序方式: 共有1609条查询结果,搜索用时 656 毫秒
1.
S R Wise  M Quigley  A W Saxe  M J Zdon 《Surgery》1990,108(6):1058-63; discussion 1063-4
Patients with hyperparathyroidism appear to be a particular risk for peptic ulcer disease. To test the hypothesis that hypercalcemia or parathyroid hormone plays a role in promoting ulcer disease, we studied the effect of varying concentrations of extracellular calcium on acid secretion using in vitro isolated rabbit gastric glands. Acid secretion was assessed by the accumulation of carbon 14-labeled aminopyrine (14C-AP). Glands were incubated with varying calcium concentrations in the unstimulated state and with histamine or carbachol (10(-7) to 10(-4) mol/L) in 1 or 2 mmol/L calcium medium. The effect of parathyroid hormone was also examined under identical conditions. Compared to 1 mmol/L standard calcium medium, unstimulated 14C-AP accumulation was significantly inhibited (p less than 0.05) at both lower (0.33 mmol/L) and higher (2 and 2.5 mmol/L) calcium concentrations. Accumulation of 14C-AP in response to histamine stimulation was unaffected by alteration of extracellular calcium (p greater than 0.2). Carbachol-stimulated 14C-AP accumulation was significantly augmented (p less than 0.01) by an increase in calcium concentration from 1 to 2 mmol/L. The addition of parathyroid hormone (10(-7) to 10(-4) mmol/L) alone or in combination with carbachol or histamine (10(-6) mmol/L) incubation did not alter 14C-AP accumulation. These data suggest that elevations in extracellular calcium play an active role in the potentiation of cholinergic-mediated gastric gland acid secretion and may thereby play a role in hyperparathyroid-related ulcer disease.  相似文献   
2.
3.
4.
Fear of falling, defined as a lack of self-confidence that one may avoid falls while doing everyday activities, may have serious consequences for elderly people. This article examines the prevalence, risk factors, and consequences of fear of falling in the elderly population; methods for assessing those fears; and suggests evidence-based interventions. Incorporating successful strategies into programs to reduce falling can result in improved patient outcomes as well as decreased healthcare utilization and costs.  相似文献   
5.
To determine if amplification of the C-erb-B2 proto-oncogene could be correlated with prognosis in carcinoid tumours, 49 pulmonary carcinoid tumours (26 typical, 23 atypical) were examined using a polyclonal antibody to the C-terminal peptide of the C-erb-B2 protein sequence. No C-erb-B2 gene product could be shown: the demonstration of C-erb-B2 does not seem to help, therefore, in determining diagnosis or prognosis in pulmonary carcinoid tumours.  相似文献   
6.
Using the Ektachem-700 multilayer film analyzer, we defined age- and sex-specific reference intervals for 20 analytes in sera from a healthy population of neonates and children ages one to 19 years. Upper and lower normal reference intervals for each analyte were determined by nonparametric methods as the 0.975 and 0.025 fractiles, respectively. Newborns have lower concentrations of total protein and albumin, and higher concentrations of phosphate, bilirubin, and enzymes in serum than older children do. Concentrations of urea, glucose, calcium, phosphate, and bilirubin change rapidly postnatally. Outside the neonatal period, no significant age- or sex-related difference was found for plasma glucose, serum amylase, conjugated or unconjugated bilirubin, or lipase. There was no sex-related difference in reference intervals for albumin, total protein, calcium, phosphate, or urea. However, concentrations of uric acid and creatine kinase are much higher in postpubertal boys than in girls. Alkaline phosphatase values peak later in boys. Except for lactate dehydrogenase and gamma-glutamyltransferase, the reference intervals defined here do not differ strikingly from data derived with use of other analyzers. The age- and sex-related trends are independent of method. However, each laboratory should determine the degree to which these reference ranges can be directly applied to analyses performed with another analyzer.  相似文献   
7.
Lower lumbar disc surgery is an extremely common operation from which vascular complications are reported rarely. However vascular injury can occur with perforation of the anterior longitudinal ligament. External haemorrhage is uncommon and the true cause of the patient's hypotension may be misdiagnosed. If the hypotension is severe or prolonged laparotomy is indicated, to prevent exsanguination and to effect a repair of the vascular injury. Alternatively, if the injury is missed, an arteriovenous fistula may develop; this diagnosis may be delayed for months or years. One case of severe haemorrhage following lower lumbar disc surgery is reported and a further 69 cases of similar arterial injury have been reviewed from the world literature.  相似文献   
8.
Although a large body of data on efficacy and safety of growth hormone (GH) treatment for various non-growth hormone-deficient (GHD) growth disorders has accumulated from a combination of clinical trial and postmarketing sources in the last 20 years or more, there remain limitations. Clinical trial data have the advantage of direct comparison of well-matched, randomized patient groups receiving treatment (or not) under comparable conditions and, as such, provide the highest quality evidence of efficacy. Clinical trials, however, are typically too small for any statistically valid assessment for safety, which is more comprehensively addressed using postmarketing data. Consequently, while the efficacy of GH treatment in children with non-GHD growth disorders has been solidly established and, based on the combination of the rigor of the clinical trial data and numerical power of the postmarketing data, no major concerns exist regarding safety, additional long-term data are required.  相似文献   
9.
10.
We analyzed blood from 450 healthy children and adolescents, ages one to 19 y, as well as term and preterm infants, to define age- and sex-specific reference intervals for numerous blood constituents. Reference intervals were derived by using nonparametric methods to determine the 0.025 and 0.975 fractiles. Ten serum proteins were measured with the Behring LN Nephelometer. Girls over 10 years of age had higher concentrations of ceruloplasmin and alpha 1-antitrypsin than other children had. There was no sex-related difference in reference intervals for the other proteins tested. Reference intervals are presented for immunoglobulins G, A, and M, complement fractions C3c and C4, ceruloplasmin, transferrin, alpha 1-antitrypsin, retinol-binding protein, and prealbumin (transthyretin).  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