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   159443篇
  免费   31728篇
  国内免费   2407篇
耳鼻咽喉   5271篇
儿科学   5622篇
妇产科学   2564篇
基础医学   4481篇
口腔科学   1601篇
临床医学   27476篇
内科学   48534篇
皮肤病学   7855篇
神经病学   15803篇
特种医学   6711篇
外国民族医学   2篇
外科学   42443篇
综合类   328篇
现状与发展   72篇
一般理论   1篇
预防医学   7620篇
眼科学   3464篇
药学   1546篇
中国医学   45篇
肿瘤学   12139篇
  2024年   689篇
  2023年   4810篇
  2022年   1244篇
  2021年   3180篇
  2020年   6106篇
  2019年   2244篇
  2018年   7507篇
  2017年   7443篇
  2016年   8532篇
  2015年   8552篇
  2014年   15635篇
  2013年   15862篇
  2012年   5807篇
  2011年   5847篇
  2010年   10573篇
  2009年   14436篇
  2008年   6081篇
  2007年   4364篇
  2006年   6824篇
  2005年   4114篇
  2004年   3331篇
  2003年   2297篇
  2002年   2382篇
  2001年   4176篇
  2000年   3365篇
  1999年   3501篇
  1998年   3770篇
  1997年   3556篇
  1996年   3434篇
  1995年   3274篇
  1994年   2004篇
  1993年   1626篇
  1992年   1535篇
  1991年   1585篇
  1990年   1185篇
  1989年   1325篇
  1988年   1173篇
  1987年   996篇
  1986年   1037篇
  1985年   822篇
  1984年   645篇
  1983年   621篇
  1982年   577篇
  1981年   453篇
  1980年   408篇
  1979年   378篇
  1978年   394篇
  1977年   456篇
  1975年   346篇
  1972年   358篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
133.
Transcranial Doppler (TCD) is an accepted modality for the evaluation of cerebral blood flow velocities. OBJECTIVES: The purpose of this study was to test the feasibility of bedside TCD measurement in the emergency department (ED) with critically ill, intubated patients. METHODS: A prospective convenience sample of patients presenting to a university hospital over a two-month period underwent TCD evaluation of the middle cerebral artery. Intubated patients with head trauma and any patient requiring tracheal intubation were eligible. A 2-MHz Doppler probe was positioned over the temporal bone to acquire blood flow velocities. An emergency medicine resident and research assistant obtained measurements. Continuous TCD tracings were recorded on a video cassette recorder tape for quality assurance review and data collection. Vital signs and therapeutic interventions were also recorded. Flow velocities were measured in cm/s; the peak Resistance Index (RI) was calculated for each patient. RESULTS: A total of 30 patients were enrolled in the study. Adequate tracings were obtained in 25 patients (83%) without a disruption of resuscitation. Tracings could not be obtained in five patients; they were listed as TCD failures. However, in two of these patients, adequate flow velocity tracings were obtained after resuscitation. Four patients were evaluated during tracheal intubation. One patient was monitored successfully during cardiopulmonary resuscitation. The median time required for data acquisition was 1.9 minutes. The mean highest RI for those who expired was 0.84. For those who survived, the mean highest RI was 0.52. The difference of 0.32 was statistically significant (p = 0.04). CONCLUSIONS: Noninvasive blood flow velocity monitoring of the middle cerebral artery using TCD is feasible in the ED when performed at the bedside on intubated patients with traumatic brain injury and others during tracheal intubation and resuscitation.  相似文献   
134.
135.
136.
PURPOSE: The aim of this study is (1) to develop a new method of risk classification for clinically localized prostate cancer; (2) to examine it in terms of compatibility with existing data such as nomograms; and (3) to compare it with existing risk-grouping methods. MATERIAL AND METHODS: The new grading system introduced here consists of three factors. The first is a prostate-specific antigen (PSA) of 4.1-10.0 ng/ml (score 0), 10.1-20.0 ng/ml (score 1), and >20.0 ng/ml (score 2). The second is a Gleason score (GS) of 6 (score 0), 7 (score 1), and 8-10 (score 2). The third is T classifications (UICC 2002) of T1c-T2a (score 0), T2b-T2c (score 1), and T3a (score 2). The sum of the three scores was named Prostate Risk Index (PRIX). Then, the compatibility of PRIX with the Partin Table, Kattan Nomogram, and Roach's formula was examined. At the same time, PRIX was compared with D'Amico, the National Comprehensive Cancer Network (NCCN), and Seattle classifications. RESULTS: PRIX 0 corresponded to 1-2% of pathologic lymph node involvement (pLN+) according to the Partin Table; PRIX 1 to 3-4%; PRIX 2 to 7-10%; PRIX 3 to 14-18%; PRIX 4 to 24-29%; PRIX 5 to 32-37%; and PRIX 6 to 42%. PRIX well separated the risks with relatively narrow ranges of probability, while D'Amico, NCCN, and Seattle classifications generally gave wide ranges especially for high-risk groups, both in the Partin Table and Kattan Nomogram. Roach's formula sometimes overestimated the risk compared to the Partin Table. CONCLUSION: PRIX fully corresponded to the Partin Table in terms of pLN+, and corresponded to the other nomograms better than any existing risk-grouping method. PRIX may thus function as a prognostic factor or contribute to patient selection in clinically localized prostate cancer.  相似文献   
137.
We report a case of successful transvenous, catheter-based, cavotricuspid isthmus ablation for treatment of atrial flutter using microwave energy. Microwave energy was delivered at 900–930 MHz using 21 W of power. Bidirectional cavotricuspid isthmus conduction block was achieved by microwave ablation without any patient discomfort or complication during the procedure. Our initial experience suggests that transcatheter microwave ablation is feasible for the cure of typical atrial flutter.  相似文献   
138.
Four Chinese patients (2 boys, 2 girls), ages 4–9 years, who had episodes of perception error of body schema and objects are reported. The metamorphopsia, which had been named Alice in Wonderland syndrome, is the major presentation. All of them were proved to have acute Epstein-Barr virus infection, as documented by positive heterophil antibody test and/or positive IgM antibody to Epstein-Barr virus capsid antigen. The duration of the perception disorder ranged from 1 week to 3 months. We believe that any young child presenting with Alice in Wonderland syndrome should undergo examination for Epstein-Barr virus infection; complete recovery from the disorder can be expected.  相似文献   
139.
140.
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