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   229734篇
  免费   5597篇
  国内免费   1682篇
耳鼻咽喉   1655篇
儿科学   7737篇
妇产科学   4188篇
基础医学   22392篇
口腔科学   2654篇
临床医学   18496篇
内科学   41654篇
皮肤病学   1804篇
神经病学   19556篇
特种医学   10095篇
外国民族医学   6篇
外科学   34873篇
综合类   8397篇
现状与发展   2篇
一般理论   9篇
预防医学   22788篇
眼科学   4009篇
药学   14344篇
  52篇
中国医学   2906篇
肿瘤学   19396篇
  2024年   135篇
  2023年   687篇
  2022年   1454篇
  2021年   2826篇
  2020年   1943篇
  2019年   1958篇
  2018年   23897篇
  2017年   19050篇
  2016年   20900篇
  2015年   3133篇
  2014年   3786篇
  2013年   4253篇
  2012年   12037篇
  2011年   25998篇
  2010年   22191篇
  2009年   14489篇
  2008年   22931篇
  2007年   25060篇
  2006年   3562篇
  2005年   4895篇
  2004年   5476篇
  2003年   6301篇
  2002年   4088篇
  2001年   717篇
  2000年   770篇
  1999年   470篇
  1998年   473篇
  1997年   453篇
  1996年   311篇
  1995年   276篇
  1994年   243篇
  1993年   173篇
  1992年   141篇
  1991年   155篇
  1990年   199篇
  1989年   143篇
  1988年   112篇
  1987年   90篇
  1986年   76篇
  1985年   78篇
  1984年   63篇
  1983年   62篇
  1982年   82篇
  1981年   66篇
  1980年   75篇
  1979年   42篇
  1976年   39篇
  1938年   60篇
  1932年   56篇
  1930年   48篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
1.
2.
3.
4.

Background and objectives

A prompt and effective management of trauma patient is necessary. The aim of this case report is to highlight the importance of intraoperative echocardiography as a useful tool in patients suffering from refractory hemodynamic instability no otherwise explained.

Case report

A 41 year‐old woman suffered a car accident. At the emergency department, no abnormalities were found in ECG or chest X‐ray. Abdominal ultrasound revealed the presence of abdominal free liquid and the patient was submitted to urgent exploratory laparotomy. Nevertheless, she persisted suffering arterial hypotension and metabolic acidosis. Looking for the reason of her hemodynamic instability, intraoperative transthoracic echocardiography was performed, finding out the presence of pericardial effusion. Once the cardiac surgeon extracted pericardial clots, patient's situation improved clinically and analytically.

Conclusion

Every anesthesiologist should be able to use the intraoperative echocardiography as an effective tool in order to establish the appropriate measures to promote the survival of patients suffering severe trauma.  相似文献   
5.
6.
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.  相似文献   
7.
8.
9.
10.
The current situation in which the humanities are disparaged affects all university disciplines, including nursing, in whose historical evolution the humanities have always been present in one form or another. Looking beyond this disrepute, this study proposes that nursing renew its attention to classical philosophy. Specifically, it invites a close reading of Xenophon's Anabasis and Plato's Meno, to get three related goals: to show how the use of ancient texts are very valuable tools for the philosophical initiation of nursing students and can help them reflect on their choice of nursing as a practical activity; to reflect on the problem of virtue and the nature of the good life; and to show how the interaction with ancient texts allows students to reflect on questions and issues of life, theirs and others, that are not open to investigation through a purely scientific method. Consequently, both Anabasis and Meno readings strengthen the intellectual relationship between philosophy and nursing, enabling the latter to delve deeper into the key questions of its own thought as a discipline.  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