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   80060篇
  免费   5847篇
  国内免费   1926篇
耳鼻咽喉   1153篇
儿科学   1437篇
妇产科学   2418篇
基础医学   10920篇
口腔科学   1369篇
临床医学   8245篇
内科学   14847篇
皮肤病学   1906篇
神经病学   5037篇
特种医学   3692篇
外国民族医学   6篇
外科学   10356篇
综合类   4303篇
现状与发展   7篇
一般理论   15篇
预防医学   4148篇
眼科学   1838篇
药学   7024篇
  22篇
中国医学   1946篇
肿瘤学   7144篇
  2024年   330篇
  2023年   644篇
  2022年   1702篇
  2021年   2688篇
  2020年   1650篇
  2019年   2054篇
  2018年   2477篇
  2017年   1955篇
  2016年   2199篇
  2015年   3204篇
  2014年   3928篇
  2013年   4515篇
  2012年   6433篇
  2011年   6119篇
  2010年   3941篇
  2009年   3354篇
  2008年   4503篇
  2007年   4448篇
  2006年   4139篇
  2005年   3826篇
  2004年   3379篇
  2003年   3211篇
  2002年   2766篇
  2001年   2088篇
  2000年   1839篇
  1999年   1489篇
  1998年   632篇
  1997年   523篇
  1996年   464篇
  1995年   406篇
  1994年   381篇
  1993年   269篇
  1992年   769篇
  1991年   634篇
  1990年   576篇
  1989年   523篇
  1988年   457篇
  1987年   458篇
  1986年   377篇
  1985年   315篇
  1984年   243篇
  1983年   202篇
  1982年   115篇
  1981年   129篇
  1980年   104篇
  1979年   219篇
  1978年   170篇
  1977年   106篇
  1976年   112篇
  1974年   109篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
Newer endoscopic techniques derived from percutaneous renal manipulations are well suited for endoscopic reconstruction of traumatic short total membranous urethral transections. Four men and 1 child underwent successful endoscopic membranous urethral reconstruction. All 4 men are voiding with good flow and normal control more than 1 year after any endoscopic manipulation.  相似文献   
104.
“C”型曲线的中耳声学特性改变与鼓室积液的关系   总被引:10,自引:2,他引:8  
对40耳声导抗检查为“C”型曲线患耳进行中耳系统共振频率点测试并进行鼓室穿刺抽液,结果表明:共振频率点低于600Hz,患耳鼓室积液阳性率为82.1%,高于600Hz患者鼓室和液阳性率16.7%,提示依据鼓室导抗图和共振频率点测定可初步判断“C”型曲线患耳鼓室积液的可能.  相似文献   
105.
MRI studies of first-pass contrast enhancement with polylysine-Gd-DTPA and myocardial tagging using spatial modulation of magnetization (SPAMM) were performed to assess the feasibility of a combined regional myocardial blood flow and 2D deformation exam. Instrumented closed-chest dogs were imaged at a baseline control state (Cntl) followed by two interventions: moderate coronary stenosis (St) achieved by partial occlusion of the left anterior descending (LAD) and moderate coronary stenosis with dobutamine loading (StD). Hypoperfusion of the anterior region (ANT) of the myocardium (LAD distribution) relative to the posterior wall (POS) based on the upslope of the signal intensity time curve from the contrast-enhanced MR images was demonstrated only with dobutamine loading (ANT:POS Cntl=1.077 ± 0.15 versus ANT:POS StD=0.477 ± 0.11, P<0.03) and was confirmed with radio-labeled microspheres measurements (ANT:POS Cntl=1.18 ± 0.2 ml/min/g versus ANT:POS StD=0.44 ± 0.1 ml/min/g; P<0.002). Significant changes in regional myocardial shortening were only seen in the StD state (P<0.02); the anterior region showed impaired myocardial shortening with dobutamine loading (P=NS), whereas the nonaffected POS region showed a marked increase in shortening when compared with Cntl (Cntl=0.964 ± 0.02 versus StD=0.884 ± 0.03; P<0.001). These results demonstrate that an integrated quantitative assessment of regional myocardial function and semiquantitative assessment of myocardial blood flow can be performed noninvasively with ultrafast MRI.  相似文献   
106.
Background. There are few data on clinical, chest radiograph (CXR) or pulmonary function sequelae in children with post-infectious bronchiolitis obliterans (BO) (pulmonary crepitations, abnormalities on CXR, CT, nuclear medicine scans, or bronchography, with a history of past pulmonary infection and in the absence of other underlying pathology). Objective. To analyse the methodology of diagnosis, long-term clinical imaging and pulmonary function sequelae of post-infectious BO in children. Materials and methods. Imaging (CXRs, CT and nuclear lung scans) and clinical histories of 19 children were analysed. Results. Clinical follow-up (mean 6.8 years), revealed a high incidence of continuing problems (asthma and bronchiectasis). Fixed airway obstruction was the most common pulmonary function sequela. The sequelae on follow-up (mean 5.8 years) CXR were classified into five patterns which are illustrated: unilateral hyperlucency of an enlarged lung/part of lung; complete collapse of the affected lobe; unilateral hyperlucency of a small or normal-sized lung; bilateral hyperlucent lungs and a mixed pattern of persistent collapse, hyperlucency and peribronchial thickening. Conclusion. Long-term observations in children with post-infectious BO should be undertaken to detect bronchiectasis and obstructive airway disease. Sequelae evident on CXR, other than those previously described, can be found. Bronchography and/or lung biopsy are not usually required for the diagnosis of post-infectious BO. Received: 15 January 1997 Accepted: 23 June 1997  相似文献   
107.
108.
109.
用酶联亲合组化法对46例肺肿瘤细胞进行了雌激素受体(ER)和孕激素受体(PR)检测。同时测定14例肺瘤肿患者血清雌二醇(E_2)浓度。结果表明:肺肿瘤 ER 阳性率为36.9%,PR 阳性率为13.0%。阳性率与性别、病理类型及血浆 E_2浓度无关。认为肺癌的发生发展可能与雌激素有依赖关系,提示内分泌疗法可能会成为原发肺肿瘤的一种治疗手段。另用 ABC 法对上述46例肺肿瘤中的29例进行了花生凝集素受体(PNA-R)和麦胚凝集素受体(WGA-R)的检测,PNA-R 在腺癌大都为顶浆型分布,鳞癌和透明细胞癌则多为胞膜型分布。结果提示 PNA-R 是肺癌分化过程中的一种标志,对肺癌分型、预后判断有一定协助作用。同时将29例肺肿瘤 PNA-R 与 ER 状况作对比研究,探讨了二者之间的相关性及可能的发生机制。  相似文献   
110.
Two clinicians and the nursing sisters working in the ICU evaluated the chance of survival of ICU patients every day. Patients were assessed either as "outcome unknown or will die." These predictions were compared with those made by computerized trend analysis of daily acute physiology and chronic health evaluation (APACHE II) scores corrected for the presence and duration of major organ system failure. The predictions were not acted upon during the study. Comparing the predictions with actual hospital outcome, the doctors and nurses had a false-positive diagnosis rate for dying of between 7.7% and 16.7%, while there were no false predictions by the computer model. The patients predicted to die by the doctors and nurses were not completely identical to those predicted by the computer. Predictions of doctors and nurses that were confirmed by the computer had a sensitivity of 20% and no false predictions of death.  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