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   104532篇
  免费   9419篇
  国内免费   6517篇
耳鼻咽喉   1096篇
儿科学   1362篇
妇产科学   900篇
基础医学   11094篇
口腔科学   1653篇
临床医学   12235篇
内科学   15398篇
皮肤病学   1233篇
神经病学   5524篇
特种医学   4639篇
外国民族医学   31篇
外科学   11917篇
综合类   18722篇
现状与发展   30篇
一般理论   11篇
预防医学   7775篇
眼科学   2205篇
药学   10797篇
  103篇
中国医学   6070篇
肿瘤学   7673篇
  2024年   343篇
  2023年   1416篇
  2022年   3633篇
  2021年   4994篇
  2020年   3797篇
  2019年   3143篇
  2018年   3306篇
  2017年   3173篇
  2016年   3158篇
  2015年   4901篇
  2014年   5854篇
  2013年   6245篇
  2012年   8968篇
  2011年   9482篇
  2010年   6953篇
  2009年   5534篇
  2008年   6521篇
  2007年   6164篇
  2006年   5636篇
  2005年   5102篇
  2004年   3787篇
  2003年   3747篇
  2002年   3027篇
  2001年   2079篇
  2000年   1651篇
  1999年   1384篇
  1998年   812篇
  1997年   777篇
  1996年   572篇
  1995年   633篇
  1994年   454篇
  1993年   298篇
  1992年   393篇
  1991年   322篇
  1990年   275篇
  1989年   270篇
  1988年   195篇
  1987年   201篇
  1986年   187篇
  1985年   128篇
  1984年   116篇
  1983年   73篇
  1982年   76篇
  1981年   67篇
  1980年   63篇
  1979年   60篇
  1978年   52篇
  1977年   43篇
  1974年   47篇
  1973年   49篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
目的探讨缺氧缺血性脑病(hypoxia-ischem ia encephalopathy,H IE)胎儿和H IE新生儿血清中促血小板生成素(Thrombopoietin,TPO)水平与脑损伤的关系,为脑瘫(cerebral palsy,CP)高危儿人群进行早期干预提供监测手段。方法收集23例H IE胎儿和34例H IE新生儿血清以及25例正常胎儿和30例正常新生儿血清,34例H IE新生儿包括11例轻度H IE,8例中度H IE和15例重度H IE。采用双抗体夹心ABC-ELISA法检测H IE胎儿组和轻、中、重H IE新生儿组血清中TPO的水平,并与正常胎儿组和正常新生儿组比较。结果H IE胎儿组和H IE新生儿组TPO分别高于正常胎儿组和正常新生儿组(分别P<0.01,P<0.01),重度H IE组TPO低于轻度H IE组(P<0.05)。结论血清TPO水平与H IE所致脑损伤严重程度有关。脐血TPO检测可为脑瘫高危儿人群进行早期干预提供监测手段。  相似文献   
42.
Ruptured aneurysms of the distal anterior choroidal artery (AchA) are extremely rare and management is dictated by clinical presentation. This report describes a rare patient with a distal AchA aneurysm and subarachnoid and intraventricular haemorrhage. A 60-year-old woman presented with a sudden onset of severe headache and vomiting. No aneurysms could be found on initial angiograms. A repeat angiogram performed 10 days after admission demonstrated an aneurysm in a branch of the cisternal segment of the left AchA without a definite neck. Surrounding vessels showed multifocal stricture and dilatation. Microsurgical clipping was not performed because the patient died suddenly due to pulmonary failure. The aetiology of the aneurysm in this case and surgical strategy are discussed.  相似文献   
43.
44.
Serum levels of bone markers N-mid osteocalcin (OCN-Mid) and Cross-Laps in 20 patients (8 men and 12 women) with loosening of at least one element of total hip endoprosthesis confirmed during operation were compared with age and sex matched group with OA. Marker levels were measured by direct chemoluminescency using Modular E-170. Statistical analysis were done with t-Student test (alpha = 0.05). There were no significant differences in OCN-Mid, Cross-Laps levels and OCN-Mid/Cross-Laps ratio between both groups. Implant loosening is a slow process taking place on a relatively small surface in comparison to whole skeleton, so bone markers have no clinical value in diagnostics of total hip loosening.  相似文献   
45.
李强  张昱苹  谢东 《海南医学》2002,13(3):18-20
目的:探讨高分辨率CT(HRCT)对颞部疾病的检查价值。方法:对43例颞部疾病患者行常规CT和高分辨率CT(HRCT)检查所获图像对比分析,并讨论HRCT的检查技术和图像后处理。结果:HRCT对病变的显示率及病变引起骨质破坏的程度,病变边缘,轮廓的显示均明显优于常规CT,尤其能清楚显示常规CT难以显示的中耳及内耳的细微结构,结论:高分辨率CT是颞部疾病的首选检查方法,使用高分辨率CT对颞部疾病的检查给临床提供更多,更准确的诊断信息。  相似文献   
46.
47.
INTRODUCTION: The purpose of this study is to investigate in vitro the effects of serotonin on the rat detrusor. In particular, it examines which drugs inhibit the serotonin-induced detrusor contractions. MATERIALS AND METHODS: Isometric tension changes of isolated rat bladder muscle strips were recorded in an organ bath using a force transducer. Acute effects of serotonin (0.0001-0.01 mM) on resting tension were assessed. Electrical field stimulation (EFS); bethanechol (0.0001-0.01 mM); ATP (1-3 mM)- or KCl (63.5-254 mM)-induced contractions using an application in an organ bath were compared with serotonin-induced contractions. In order to examine the action mechanism of serotonin-induced stimulation, EFS-, bethanechol-, ATP- or KCl-induced contraction on serotonin treatment (0.001 mM) was assessed and serotonin (0.001-0.1 mM) was cumulatively added to the organ bath following preincubation with propranolol, ketanserin, tropisetron, propiverine, sodium nitroprusside or doxazosin. RESULTS: The serotonin-induced response has two phases: an initial transient contraction and a prolonged tonic phase. Serotonin produced a reversible and dose-dependent contraction of the detrusor strips. Responses to bethanechol significantly increased with a concentration of 0.001 mM serotonin (p < 0.05). There was no effect on the responses to ATP, KCl, or EFS on 0.001 mM serotonin. The 5-HT(2) receptor is mainly responsible for serotonin-induced contractions of the detrusor (p < 0.05), while the 5-HT(1) receptor is partially responsible. Doxazosin and propiverine each significantly suppressed the response to serotonin, while sodium nitroprusside and tropisetron each had no effect (p < 0.05). CONCLUSIONS: Because the 5-HT(2) antagonist blocked the effect of serotonin-induced bladder contractions and the stimulation of the adrenoreceptors, the 5-HT(2) antagonist seems to improve lower urinary tract symptoms.  相似文献   
48.
The fit and fill of the femoral canal are critical to the success of cementless femoral stems in total hip arthroplasty. It is difficult for conventional stems to provide a good fit and fill for the femora of patients with secondary osteoarthritis. Based on measurements of 100 femora of these patients, we designed two types of Fukui Medical School (FMS) stems with a proximal lateral flare that differed in the medial radius. We compared the fit and fill of the FMS stems with those of four conventional stems, using computer simulation. The mean proximal fit and total fit of the FMS stems were 46% and 53% respectively, a significant improvement compared with the other stems examined. The mean fill of FMS stems was 82% at the lower end of the lesser trochanter and 84% at the upper end of the isthmus, values that were significantly higher than those of the other stems. Since September 1995, we have implanted FMS stems in 15 hips with secondary osteoarthritis. Radiographic evaluations showed that the canal fill of the FMS stems was significantly greater in the proximal femur compared with other stems previously inserted at our department. A summary of this paper was presented at the 9th Symposium on Computer-Assisted Radiology; June 1995, Berlin, and at the 8th International Symposium on Technology in Arthroplasty; September 1995, Puerto Rico.  相似文献   
49.
本实验制作不同程度心肌缺血的动物模型,以声处理5%人血白蛋白为超声造影剂进行心肌灌注造影,探讨MCE时间-强度曲线各指标与心肌缺血程度间的关系。结果表明:心肌显影的峰值强度和曲线下面积均与缺血程度呈显著负相关(相关系数分别为r=-0.98,P值<0.005;r=-0.94,P值<0.05),且能区分轻度、中度和重度三种程度的心肌缺血;而三项时间指标与心肌缺血程度间未发现显著性差异。本实验的初步结果表明,MCE是一项活体评估局部心肌血流灌注的有效方法。  相似文献   
50.
This study presents the result of 12–21 years' follow-up in a group of children with neonatal urinary tract infection (onset within 1 month after birth) in whom early renal growth retardation was noted without concomitant classical renal scarring. In all cases the neonatal infection was diagnosed and treated within a few days of onset and the patients were closely supervised thereafter. Renal length, parenchymal thickness and area were measured at urography. At first follow-up (22 children, mean age 4.1 years) a significant reduction of renal parenchymal thickness was noted. Long-term follow-up (18 patients, mean age 17 years) demonstrated a normalization of renal size in the entire group, although less complete in the subgroup with reflux. There were two major findings in the present study. Firstly, renal growth retardation was seen after neonatal infection, both with and without reflux. Secondly, normalization of renal size in previously small kidneys was demonstrated, suggesting that growth retardation can be a reversible phenomenon. The tendency for such normalization was slightly more marked in children without reflux. Reduction of parenchymal thickness without calyceal deformity, therefore, does not necessarily mean irreversible damage, and differentiation between permanent scarring and temporary growth retardation can thus only be made at later follow-up, possibly not until after puberty. The demonstration of renal growth retardation in spite of early diagnosis and treatment emphasizes the great vulnerability of the kidney in the newborn.  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