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   125074篇
  免费   7597篇
  国内免费   1087篇
耳鼻咽喉   1929篇
儿科学   1912篇
妇产科学   1872篇
基础医学   19989篇
口腔科学   3061篇
临床医学   11682篇
内科学   22174篇
皮肤病学   3948篇
神经病学   10200篇
特种医学   7212篇
外科学   16582篇
综合类   520篇
现状与发展   3篇
一般理论   27篇
预防医学   6534篇
眼科学   3151篇
药学   11342篇
中国医学   1455篇
肿瘤学   10165篇
  2023年   666篇
  2022年   1554篇
  2021年   4392篇
  2020年   2105篇
  2019年   2943篇
  2018年   3676篇
  2017年   2990篇
  2016年   3900篇
  2015年   5434篇
  2014年   6438篇
  2013年   7501篇
  2012年   11241篇
  2011年   10779篇
  2010年   6164篇
  2009年   5291篇
  2008年   7528篇
  2007年   7151篇
  2006年   6463篇
  2005年   5979篇
  2004年   5212篇
  2003年   4536篇
  2002年   3902篇
  2001年   3032篇
  2000年   2786篇
  1999年   2136篇
  1998年   905篇
  1997年   666篇
  1996年   507篇
  1995年   450篇
  1994年   388篇
  1993年   331篇
  1992年   746篇
  1991年   695篇
  1990年   638篇
  1989年   555篇
  1988年   464篇
  1987年   466篇
  1986年   332篇
  1985年   368篇
  1984年   261篇
  1983年   191篇
  1982年   132篇
  1981年   168篇
  1980年   128篇
  1979年   222篇
  1978年   162篇
  1976年   132篇
  1975年   120篇
  1974年   139篇
  1973年   119篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Rationale:The prone position is commonly used in spinal surgery. There have been many studies on hemodynamic changes in the prone position during general anesthesia. We report a rare case of transient left bundle branch block (LBBB) in a prone position.Patient concern:Electrocardiogram (ECG) of a 64-year-old man scheduled for spinal surgery showed normal sinus rhythm change to LBBB after posture change to the prone position.Diagnosis:Twelve lead ECG revealed LBBB. His coronary angio-computed tomography results showed right coronary artery with 30% to 40% stenosis and left circumflex artery with 40% to 50% stenosis. The patient was diagnosed with stable angina and second-degree atrioventricular block of Mobitz type II.Intervention:Nitroglycerin was administered intravenously during surgery. Adequate oxygen was supplied to the patient. After surgery, the patient was prescribed clopidogrel, statins, angiotensin II receptor blocker, and a permanent pacemaker was inserted.Outcome:Surgery was completed without complications. After surgery, the transient LBBB changed to a normal sinus rhythm. The patient did not complain of chest pain or dyspnea.Lesson:The prone position causes significant hemodynamic changes. A high risk of cardiovascular disease may cause ischemic heart disease and ECG changes. Therefore, careful management is necessary.  相似文献   
85.
86.
87.
Fast CT-PRESS-based spiral chemical shift imaging at 3 Tesla.   总被引:2,自引:0,他引:2  
A new sequence is presented that combines constant-time point-resolved spectroscopy (CT-PRESS) with fast spiral chemical shift imaging. It allows the acquisition of multivoxel spectra without line splitting with a minimum total measurement time of less than 5 min for a field of view of 24 cm and a nominal 1.5x1.5-cm2 in-plane resolution. Measurements were performed with 17 CS encoding steps in t1 (Deltat1=12.8 ms) and an average echo time of 151 ms, which was determined by simulating the CT-PRESS experiment for the spin systems of glutamate (Glu) and myo-inositol (mI). Signals from N-acetyl-aspartate, total creatine, choline-containing compounds (Cho), Glu, and mI were detected in a healthy volunteer with no or only minor baseline distortions within 14 min on a 3 T MR scanner.  相似文献   
88.
Although surgical lung resection could improve prognosis in some patients with multidrug-resistant tuberculosis (MDR-TB), there are no reports on the optimal candidates for this surgery. The aim of the present study was to elucidate the prognostic factors for surgery in patients with MDR-TB. Patients who underwent lung resection for the treatment of MDR-TB between March 1993 and December 2004 were included in the present study. Treatment failure was defined as greater than or equal to two of the five cultures recorded in the final 12 months of treatment being positive, any one of the final three cultures being positive, or the patient having died during treatment. The variables that affected treatment outcomes were identified through univariate and multivariate logistic regression analysis. In total, 79 patients with MDR-TB were included in the present study. The treatment outcomes of 22 (27.8%) patients were classified as failure. A body mass index <18.5 kg x m(-2), primary resistance, resistance to ofloxacin and the presence of a cavitary lesion beyond the range of the surgical resection were associated with treatment failure. Low body mass index, primary resistance, resistance to ofloxacin and cavitary lesions beyond the range of resection are possible poor prognostic factors for surgical lung resection in multidrug-resistant tuberculosis patients.  相似文献   
89.
Generally, a computed tomography scan is conducted for the diagnosis of stroke in the emergency department, because these scans are easier and faster in the detection of stroke. If there are no signs of hemorrhage on computed tomography scan, an ischemic stroke is diagnosed and treated accordingly. A magnetic resonance imaging scan may be taken in order to verify ischemic stroke. This process may lead to improper treatment and is time consuming. To address this situation, case studies are presented in which magnetic resonance imaging diffusion-weighted imaging and gradient recalled echo were performed to detect hemorrhagic and ischemic stroke and particularly, subarachnoid hemorrhage, which is undetectable with a computed tomography scan.  相似文献   
90.
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