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   2369149篇
  免费   187792篇
  国内免费   4639篇
耳鼻咽喉   33177篇
儿科学   80076篇
妇产科学   66873篇
基础医学   337258篇
口腔科学   64573篇
临床医学   212224篇
内科学   469587篇
皮肤病学   53556篇
神经病学   191542篇
特种医学   92145篇
外国民族医学   1051篇
外科学   359178篇
综合类   53979篇
现状与发展   4篇
一般理论   783篇
预防医学   184907篇
眼科学   53730篇
药学   171805篇
  3篇
中国医学   5053篇
肿瘤学   130076篇
  2019年   18268篇
  2018年   26097篇
  2017年   19767篇
  2016年   22084篇
  2015年   24821篇
  2014年   35009篇
  2013年   52703篇
  2012年   72032篇
  2011年   76393篇
  2010年   45290篇
  2009年   43088篇
  2008年   71518篇
  2007年   76164篇
  2006年   76751篇
  2005年   74614篇
  2004年   72013篇
  2003年   69004篇
  2002年   67298篇
  2001年   116553篇
  2000年   120040篇
  1999年   100957篇
  1998年   28190篇
  1997年   25438篇
  1996年   25814篇
  1995年   24539篇
  1994年   22641篇
  1993年   21181篇
  1992年   78021篇
  1991年   75335篇
  1990年   72784篇
  1989年   69397篇
  1988年   63809篇
  1987年   62600篇
  1986年   58439篇
  1985年   55907篇
  1984年   42388篇
  1983年   35758篇
  1982年   21347篇
  1981年   19165篇
  1979年   37742篇
  1978年   26457篇
  1977年   22138篇
  1976年   20854篇
  1975年   22074篇
  1974年   26192篇
  1973年   25283篇
  1972年   23460篇
  1971年   21295篇
  1970年   20223篇
  1969年   18489篇
排序方式: 共有10000条查询结果,搜索用时 484 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