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   716篇
  免费   46篇
  国内免费   7篇
耳鼻咽喉   2篇
儿科学   43篇
妇产科学   14篇
基础医学   71篇
口腔科学   39篇
临床医学   54篇
内科学   152篇
皮肤病学   8篇
神经病学   41篇
特种医学   90篇
外科学   76篇
综合类   64篇
预防医学   42篇
眼科学   11篇
药学   33篇
中国医学   1篇
肿瘤学   28篇
  2023年   3篇
  2022年   5篇
  2021年   7篇
  2020年   7篇
  2019年   5篇
  2018年   11篇
  2017年   8篇
  2016年   11篇
  2015年   18篇
  2014年   12篇
  2013年   29篇
  2012年   21篇
  2011年   27篇
  2010年   25篇
  2009年   36篇
  2008年   21篇
  2007年   31篇
  2006年   41篇
  2005年   23篇
  2004年   18篇
  2003年   16篇
  2002年   13篇
  2001年   19篇
  2000年   11篇
  1999年   18篇
  1998年   45篇
  1997年   32篇
  1996年   41篇
  1995年   17篇
  1994年   19篇
  1993年   22篇
  1992年   7篇
  1991年   9篇
  1990年   4篇
  1989年   13篇
  1988年   27篇
  1987年   13篇
  1986年   8篇
  1985年   20篇
  1984年   9篇
  1983年   7篇
  1982年   4篇
  1981年   5篇
  1980年   3篇
  1977年   5篇
  1976年   8篇
  1975年   6篇
  1974年   2篇
  1967年   2篇
  1965年   1篇
排序方式: 共有769条查询结果,搜索用时 31 毫秒
41.
Roxatidine acetate, a new H2 receptor antagonist, was compared with ranitidine in the treatment of duodenal ulcers in a double-blind multicentre study. Eighty-four patients with endoscopically proven duodenal ulcer were randomized to receive 150 mg roxatidine acetate or 300 mg ranitidine at bedtime. Repeat endoscopy was performed after 4 weeks (25–33 days) and if the ulcer had not healed, another endoscopy was performed after a further 4 weeks of treatment. Using per protocol analysis 73.6% of ulcers treated with roxatidine healed at 4 weeks compared to 72.2% of ulcers treated with ranitidine (P=NS). The healing rates at 8 weeks were 92% with roxatidine and 83.3% with ranitidine (P=NS). Using equivalence tests, the healing rate of roxatidine was found to be equivalent to that of ranitidine within a 20% region. Roxatidine users took significantly less antacids than ranitidine users (P < 0.05). There were no significant adverse effects due to roxatidine or ranitidine. Roxatidine is a safe effective drug in the treatment of duodenal ulcers with a healing rate comparable to that of ranitidine.  相似文献   
42.
Pathologic changes in 3-methylindole-induced equine bronchiolitis   总被引:2,自引:2,他引:0       下载免费PDF全文
The pathologic features of bronchiolitis were studied in horses and ponies from 30 minutes to 27 days after an oral dose of 3-methylindole (3MI). From 30 minutes to 3 hours, lesions were limited to nonciliated bronchiolar epithelial (Clara) cells, which lost apical caps and cytoplasmic granules and had dilated smooth endoplasmic reticulum (SER). At 12 hours, necrotic Clara cells were exfoliated; degeneration and necrosis were evident, in bronchiolar ciliated cells. Rare epithelial cells with hyperplastic SER appeared on the denuded basal lamina at 24 hours. Inflammatory cells, epithelia, fibroblastlike cells, collagen, and debris occluded many bronchiolar lumens from 3 to 6 days. Reorganization resulted in a simple columnar bronchiolar epithelium with relatively normal ciliated cells and fewer fibroblastlike cells. However, mature Clara cells were rare at 27 days, and collagenous bands still divided bronchiolar lumens. Thus, 3MI toxicosis is a persistent model of equine bronchiolitis with many morphologic features of the spontaneous disease.  相似文献   
43.
Thallium-201/technetium-99m pertechnetate subtraction scintigraphy of the parathyroid glands was performed in a prospective study of 33 patients who had undergone bilateral neck exploration for elevated serum calcium and serum parathyroid hormone levels. In 31 cases, the Tl-201/Tc-99m subtraction technique yielded an overall sensitivity of 81%, specificity of 99%, and accuracy of 94% for identifying solitary parathyroid adenomas. Tl-201/Tc-99m subtraction scintigraphy correctly identified 73% of parathyroid adenomas weighing less than 499 mg, 79% of those weighing 500-1,499 mg, and 100% of adenomas weighing more than 1,500 mg. In a subgroup of 24 patients with solitary parathyroid adenomas who underwent both scintigraphy and high-resolution sonography, the sensitivity, specificity, and accuracy of both procedures were similar.  相似文献   
44.
BACKGROUND: There is a shortage of research studies that assess how selected characteristics of neighbourhood and personal social circumstances contribute towards health-related quality of life (QoL) among older people. METHODS: Analysis of baseline data for 5581 people aged > or =75 years and over from the Trial of Assessment and Management of Older People in the Community. The scores for four dimensions from the UK version of the Sickness Impact Profile and for the Philadelphia Geriatric Morale Scale were analysed in relation to individual social class and the Carstairs score of socioeconomic deprivation for the enumeration district of residence. RESULTS: In age and sex adjusted analyses, the proportion of participants of social class IV/V living in the most deprived areas who were in the quintile with worst QoL scores was more than double that among those from social class I/II living in the least deprived areas. Individual social class and area deprivation score contributed roughly equally to this doubling for home management, self-care and social interaction, whereas social class appeared a stronger determinant for mobility. Adjustment for living circumstances, health symptoms, and health behaviours substantially reduced the excess risk associated with social class and area deprivation. Being in a rural area was associated with lower risk of poor morale. CONCLUSION: Poor socioeconomic characteristics of both the area and the individual are associated with worse functioning (QoL) of older people in the community. This is not fully explained by health status. Policy should consider community-level interventions as well as those directed at individuals.  相似文献   
45.
46.
The NBT test is a non-specific test of neutrophil membrane stimulation which has application to the study of neutrophil function, particularly in the septicaemic patient. An improved cytochemical test which eliminates potential sources of laboratory error has been developed. Venous or capillary blood samples may be studied and the technique can be applied to the neutropenic patient since available neutrophils are concentrated by cytocentrifugation. Clinical evaluation in 443 patients is described.  相似文献   
47.
In 42 children with congenital heart disease coagulation factor levels were studied serially during the first 20 hours following cardiopulmonary bypass surgery. The acyanotic patients, and also cyanotic patients who survived the operation, showed a progressive improvement in their coagulation profile from initial low postoperative levels. In 12 cyanotic patients who died within 72 hours, however, the coagulation factor levels either remained low, or fell further, until death. Fresh frozen plasma was administered to eight of these patients without apparent benefit. The abnormal coagulation profile correlated significantly with low skin temperature and increased blood loss and was considered to represent excess intravascular coagulation secondary to low cardiac output and poor tissue perfusion.  相似文献   
48.
49.
The authors studied the validity of the Clock-Drawing Test (CDT) in comparison with the Mini-Mental State Examination (MMSE) and the association between the CDT and mortality in a large general population sample of persons aged 75 years or more. Data were obtained from the MRC Trial of the Assessment and Management of Older People in the Community. Baseline assessments were conducted between 1995 and 1999 in the United Kingdom. A total of 13,557 subjects with both CDT and MMSE scores were included in the analysis. The median follow-up period was 4.7 years. The sensitivity and specificity of the CDT for detecting moderate-to-severe cognitive impairment (MMSE score 相似文献   
50.
BACKGROUND: Embryonic nigral cell implants are a novel treatment for Parkinson disease (PD). Reaction time (RT) and movement time (MT) analysis, validated quantitative measures of premovement neural processing and motor execution, can be used as objective physiological markers of motor performance in PD. OBJECTIVES: To gauge the change in motor performance in patients with PD who received implants, and to determine whether the physiological findings correlate with clinical outcome measures after transplantation. DESIGN: Double-blind, placebo-controlled trial.Patients Forty patients with levodopa-responsive, Hoehn and Yahr stage III or greater PD. INTERVENTIONS: Random assignment to embryonic tissue implants or placebo (sham) operation. MAIN OUTCOME MEASURES: Combined RT + MT scores measured preoperatively and at 4 and 12 months postoperatively in the "off" state. RESULTS: The difference in mean RT + MT scores between the sham and implant groups was statistically significant (P =.005) and was greatest in those 60 years or older (P =.003). Changes correlated with Unified Parkinson's Disease Rating Scale off scores at 4 (r = 0.87, P =.001) and 12 (r = 0.75, P =.01) months in those younger than 60 years. There was a significant deterioration in the sham surgery group at 12 months (P =.03) that was thought to be due to worsening in subjects 60 years and older (P<.001). CONCLUSIONS: The physiological measures detected significant changes in patients undergoing embryonic nigral cell implants and correlated directly with clinical outcome measures. Comprehensive analyses of RT paradigms can document subtle changes in motor performance over time, making them useful outcome measures in therapeutic trials of PD. These findings support further research into nigral cell implantation for PD.  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