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   1512071篇
  免费   106708篇
  国内免费   2539篇
耳鼻咽喉   20821篇
儿科学   44749篇
妇产科学   38186篇
基础医学   223944篇
口腔科学   44875篇
临床医学   134012篇
内科学   290919篇
皮肤病学   32750篇
神经病学   112875篇
特种医学   57549篇
外国民族医学   151篇
外科学   236431篇
综合类   31110篇
现状与发展   2篇
一般理论   382篇
预防医学   106150篇
眼科学   35277篇
药学   116669篇
  4篇
中国医学   4202篇
肿瘤学   90260篇
  2018年   15455篇
  2017年   12043篇
  2016年   13408篇
  2015年   15081篇
  2014年   20610篇
  2013年   30629篇
  2012年   41201篇
  2011年   43292篇
  2010年   25617篇
  2009年   24325篇
  2008年   41364篇
  2007年   43760篇
  2006年   44929篇
  2005年   42590篇
  2004年   41345篇
  2003年   39491篇
  2002年   38681篇
  2001年   81857篇
  2000年   84002篇
  1999年   69795篇
  1998年   17189篇
  1997年   14963篇
  1996年   15262篇
  1995年   14384篇
  1994年   13301篇
  1993年   12224篇
  1992年   53293篇
  1991年   51991篇
  1990年   50222篇
  1989年   49263篇
  1988年   44766篇
  1987年   43633篇
  1986年   41066篇
  1985年   39003篇
  1984年   28191篇
  1983年   23960篇
  1982年   12768篇
  1981年   11220篇
  1979年   25398篇
  1978年   17446篇
  1977年   14884篇
  1976年   13590篇
  1975年   14925篇
  1974年   17856篇
  1973年   17014篇
  1972年   16079篇
  1971年   15112篇
  1970年   14462篇
  1969年   13478篇
  1968年   12345篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The aim of the current study was to investigate whether alterations in N-terminal pro brain natriuretic peptide (NT-proBNP) reflect changes in right ventricular structure and function in pulmonary hypertension patients during treatment. The study consisted of 30 pulmonary hypertension patients; 15 newly diagnosed and 15 on long-term treatment. NT-proBNP, right heart catheterisation and cardiac magnetic resonance imaging measurements were performed, at baseline and follow-up. There were no significant differences between newly diagnosed patients and those on treatment at baseline or follow-up with respect to NT-proBNP, haemodynamics and right ventricular parameters. Relative changes in NT-proBNP during treatment were correlated to the relative changes in right ventricular end-diastolic volume index (r = 0.59), right ventricular mass index (r = 0.62) and right ventricular ejection fraction (r = -0.81). N-terminal pro brain natriuretic peptide measurements reflect changes in magnetic resonance imaging-measured right ventricular structure and function in pulmonary hypertension patients. An increase in N-terminal pro brain natriuretic peptide over time reflects right ventricular dilatation concomitant to hypertrophy and deterioration of systolic function.  相似文献   
72.
73.
74.
75.
76.
BACKGROUND: The incidence of malignant melanoma of the skin has risen in every part of the world where reliable cancer registration data are found. OBJECTIVE: Our study aims to describe the changing incidence of and survival from invasive cutaneous malignant melanoma in Malta, by analysing the data from the 211 cases that were registered at the Malta National Cancer Registry between 1993 and 2002. RESULTS: The age standardized incidence rates for invasive cutaneous malignant melanoma rose from 3.7 per 100,000 population per year for males and 5.1 for females in the first 5-year period, to 8.0 per 100,000 population per year for males and 5.9 for females in the second 5-year period. In both sexes, numbers of thin (< or = 1.0 mm) invasive melanomas increased significantly between 1993 and 2002; males also registered a significant increase in intermediate-thickness (1.01-4.0 mm) melanomas. The increase in numbers of thin and intermediate-thickness melanomas between the two 5-year periods was greatest in patients aged 60 years and over. The overall absolute 5-year survival rate for the first period was 74% and for the second period 92%. CONCLUSION: Numbers of reported cases of invasive cutaneous malignant melanoma in Malta have more than doubled during the 10-year study period. This is mostly due to a marked rise in the diagnosis of thin melanomas in both sexes, occurring mainly in patients aged 60 years and over. As thin melanomas are of low metastasizing potential, this has resulted in an increase in survival between the two 5-year study periods.  相似文献   
77.
78.
BACKGROUND AND OBJECTIVES: In 1999, our institution began a kidney transplant program with collaboration between the departments of General Surgery/Transplantation and Urology. From the onset, donor nephrectomies were performed laparoscopically and are currently the domain of Urology, which had no prior laparoscopic experience before this undertaking. We reviewed our experience. METHODS: A database of our experience was kept prospectively from June 1999 to November 2004. Records of both donors and recipients were reviewed. Special attention was directed toward our changes in technique and their relationship to outcomes, with emphasis on graft extraction and overall complication rates. RESULTS: We reviewed the records of 205 consecutive procedures. We report excellent donor outcomes, including mean operative time (112 minutes), estimated blood loss (120 mL), and length of stay (2.3 days). Complication (14.1%) and open conversion (1.5%) rates were low. For the recipients, early (98.0%) and 1-year (94.7%) graft survival, and ureteral ischemia (2.4%) rates were also appropriate with contemporary experience. CONCLUSIONS: We report our results on laparoscopic donor nephrectomy in a de novo renal transplant program. Because of this experience, we have ventured into other horizons of urologic laparoscopy and currently produce enough volume to support a laparoscopic fellowship. We feel that a productive donor nephrectomy program can enhance urologic laparoscopic programs and should be taken advantage of when available.  相似文献   
79.
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel analysis among Swiss adolescents

Objective:  

To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels.  相似文献   
80.
Complex regional pain syndrome (CRPS) was formerly known as “Sudeck’s atrophy”. The disease belongs to the group of neuropathic pain syndromes and is differentiated into three types. Type I is characterized by a lack of nerve lesions, type II by the presence of nerve lesions, and type III by the presence of other entities such as fibromyalgia. The exact pathogenic factors leading to the disease are still unknown and are currently the subject of investigation in various studies. These studies suggest a contribution of the central nervous system to the development and maintenance of CRPS. However, the clinical symptoms are well documented and include pain, autonomic changes and impaired motor function of the affected extremity. Diagnosis is based clinically on signs and symptoms. However, in a few cases radiography and scintiscanning may be useful to finalize the diagnosis. The treatment options are centred on the symptoms of pain, autonomic changes and functional impairment. A multidisciplinary treatment strategy is recommended, with surgeons, anaesthesiologists, physiotherapists and psychotherapists working together. Surgical intervention in this disease is only required in rare cases of neurological and bone pain, and the indications for such intervention are narrow and should be strictly observed.  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