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   2367465篇
  免费   187628篇
  国内免费   4637篇
耳鼻咽喉   33144篇
儿科学   80014篇
妇产科学   66833篇
基础医学   337098篇
口腔科学   64499篇
临床医学   212028篇
内科学   469135篇
皮肤病学   53520篇
神经病学   191390篇
特种医学   92102篇
外国民族医学   1051篇
外科学   358994篇
综合类   53927篇
现状与发展   4篇
一般理论   782篇
预防医学   184753篇
眼科学   53711篇
药学   171707篇
  3篇
中国医学   5053篇
肿瘤学   129982篇
  2019年   18242篇
  2018年   26064篇
  2017年   19737篇
  2016年   22053篇
  2015年   24796篇
  2014年   34968篇
  2013年   52641篇
  2012年   71935篇
  2011年   76298篇
  2010年   45204篇
  2009年   43022篇
  2008年   71447篇
  2007年   76063篇
  2006年   76669篇
  2005年   74534篇
  2004年   71938篇
  2003年   68942篇
  2002年   67252篇
  2001年   116511篇
  2000年   119997篇
  1999年   100917篇
  1998年   28161篇
  1997年   25418篇
  1996年   25795篇
  1995年   24508篇
  1994年   22617篇
  1993年   21154篇
  1992年   77987篇
  1991年   75303篇
  1990年   72748篇
  1989年   69363篇
  1988年   63788篇
  1987年   62565篇
  1986年   58431篇
  1985年   55895篇
  1984年   42376篇
  1983年   35742篇
  1982年   21339篇
  1981年   19156篇
  1979年   37732篇
  1978年   26440篇
  1977年   22129篇
  1976年   20846篇
  1975年   22064篇
  1974年   26181篇
  1973年   25272篇
  1972年   23456篇
  1971年   21286篇
  1970年   20219篇
  1969年   18484篇
排序方式: 共有10000条查询结果,搜索用时 558 毫秒
991.
OBJECTIVE: evaluation and comparison of the endovascular treatment of isolated aortic and aortoiliac atherosclerotic lesions (stenoses and occlusions). METHODS: a percutaneous endovascular procedure was performed in 52 patients (38 men and 14 women) with a mean age of 52 years (range, 25-85 years). The baseline angiogram showed 35 aortic lesions (31 stenoses, 4 occlusions) and 17 aortoiliac lesions (14 stenoses, 3 occlusions). Percutaneous techniques used in this series included variable combinations of transluminal angioplasty and stenting. All stents placements were performed over-the-wire using the transfemoral route (most often bilateral approach). Clinical examination and Duplex-scan were performed at discharge, 1 month, 6 months, 12 months, and then yearly. RESULTS: technical success was 100% for aortic and aortoiliac lesions. Angiographic success rates were comparable for aortic (91%) and aortoiliac (94%) lesions. No death occurred during or early after the endovascular intervention. Duplex-scan confirmed 100% patency rate at discharge. There was no significant difference between the aortic (94%) and aortoiliac (96%) groups regarding immediate clinical improvement. Mean follow-up was 34+/-31 months (range, 0-130 months). The cumulative primary patency rate at 36 months was 85% in the aortic group and 86% in the aortoiliac group. Clinical success, defined as a symptom-free status at the end of follow-up, was also similar in both groups. CONCLUSION: endovascular treatment of isolated aortic lesions of the infra-renal aorta has favorable outcomes comparable to those of aortoiliac lesions.  相似文献   
992.
993.
In der Behandlung von Frakturen spielt die Analgesie eine wesentliche Rolle. Es stellt sich daher die Frage, ob in der Klinik h?ufig eingesetzte Analgetika wie Tramadol oder Diclofenac negative Wirkungen auf die Knochenbruchheilung haben.  相似文献   
994.
Aims Objective of this study was to investigate whether adenosine modulates renal erythropoietin production.
Methods In the present study erythropoietin production was stimulated by hypobaric hypoxia by subjecting healthy volunteers to a simulated altitude of 4000  m in a low pressure chamber for 5.5  h. During exposure to hypoxia the subjects received i.v. in a randomized, single-blind, cross-over fashion the non-specific adenosine antagonist theophylline, the adenosine reuptake inhibitor dipyridamole and placebo.
Results Contrary to the working hypothesis, theophylline did not decrease and dipyridamole did not further boost erythropoietin concentrations.
Conclusions The results are in agreement with our earlier study using haemorrhage as a controlled physiological stimulus of erythropoietin production, and would question a major role for adenosine as a mediator of renal erythropoietin production.  相似文献   
995.
996.
997.
Summary Early recognition of recurrence and work-up of clinically indeterminate lesions may be impaired after reconstruction with silicone implants due to superimposition of the implant or to scarring. This study was undertaken to evaluate the use of contrast-enhanced MRI in patients with silicone implant after breast cancer. Contrast-enhanded MRI was offered to 169 patients. Comparative two- to three-view mammography was also performed in 169 patients, as well as comparative sonography in 144 patients. Conventional imaging and clinical examination detected only 8/13 recurrences, whereas 12/13 were detected by MRI. One recurrence had been visible as a strongly enhancing 2-mm dot in a previous examination (2 years before), but was not called. It was therefore counted as false negative. In addition, multicentricity was detected by MRI alone in two of three cases. MRI correctly diagnosed scar tissue in all cases with indeterminate findings. However, due to false-positive calls caused by enhancing granulomas specificity could not be improved. Contrast-enhanded MRI allowed decisive additional information in our study group and improved the sensitivity significantly (concerning all diagnoses). Contrast-enhanded MRI is recommended in patients with diagnostic problems or high risk of recurrence after silicone implants.   相似文献   
998.
999.
采用荧光法测定负载Fura-2/AM大脑皮层突触体内游离钙「Ca^2+」i浓度大鼠感染性脑损伤中的变化及其意义。  相似文献   
1000.
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