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   195413篇
  免费   4121篇
  国内免费   446篇
耳鼻咽喉   2799篇
儿科学   7448篇
妇产科学   5868篇
基础医学   25273篇
口腔科学   5794篇
临床医学   15278篇
内科学   35222篇
皮肤病学   4572篇
神经病学   11658篇
特种医学   10807篇
外国民族医学   97篇
外科学   29326篇
综合类   1089篇
一般理论   2篇
预防医学   16291篇
眼科学   4303篇
药学   13527篇
  2篇
中国医学   151篇
肿瘤学   10473篇
  2018年   3578篇
  2017年   3917篇
  2016年   3230篇
  2015年   4921篇
  2014年   4345篇
  2013年   3446篇
  2012年   9897篇
  2011年   4769篇
  2010年   2196篇
  2009年   3851篇
  2008年   2078篇
  2007年   2790篇
  2006年   3040篇
  2005年   11157篇
  2004年   12613篇
  2003年   8199篇
  2002年   3432篇
  2001年   4329篇
  2000年   1698篇
  1999年   5855篇
  1998年   514篇
  1995年   375篇
  1992年   6858篇
  1991年   7093篇
  1990年   7345篇
  1989年   6944篇
  1988年   6473篇
  1987年   6236篇
  1986年   5950篇
  1985年   5242篇
  1984年   3591篇
  1983年   2908篇
  1982年   1002篇
  1981年   772篇
  1980年   842篇
  1979年   3831篇
  1978年   2365篇
  1977年   1790篇
  1976年   1561篇
  1975年   2475篇
  1974年   3109篇
  1973年   2741篇
  1972年   2757篇
  1971年   2745篇
  1970年   2560篇
  1969年   2466篇
  1968年   2239篇
  1967年   2163篇
  1966年   1898篇
  1965年   1131篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
To study the hemostyptic effect of aprotinin (Trasylol) in patients undergoing extracorporeal circulation for coronary artery bypass operations, we randomized 12 of 24 patients to receive aprotinin in high dosage (about 800 mg) during extracorporeal circulation. From the resulting two groups each, one patient was excluded from the study because of postoperative myocardial infarction (control group) and surgical hemorrhage (aprotinin group) leading to a second operation. Although heparin was used for anticoagulation in all 22 patients, all had a marked increase in plasma levels of thrombin-antithrombin III complexes during extracorporeal circulation, indicating an intravasal activation of coagulation. By monitoring the plasma levels of fibrin degradation products in patients without aprotinin therapy, we recorded a concomitant hyperfibrinolysis significantly less pronounced in patients receiving aprotinin (p less than 0.005). The mean total postoperative blood loss was lower in patients receiving aprotinin (620 ml) than in control patients (1000 ml; p less than 0.03). The results confirm previous reports of a hemostyptic effect of aprotinin in cardiac operations. This effect is probably due to a prevention of hyperfibrinolysis.  相似文献   
102.
Thirty-five members of a family affected with von Hippel-Lindau's disease (VHL) were examined and lesions were found in nine of them. Four of the lesions were located in the central nervous system; two cerebellar, one spinal, one cerebral. Eye lesions were present in eight of the nine patients and complications developed in seven; six unilateral and one bilateral blindness. Both mortality and morbidity were found to be higher than in other series. This is attributed to insufficient screening of the patients with familial VHL, the late diagnosis was established only after the onset of complications. The importance of screening tests in VHL risk patients is emphasized.  相似文献   
103.
104.
105.
Reported in this paper are postoperative results recorded from 120 patients, 3 years after selective proximal vagotomy for uncomplicated duodenal ulcer. There was no intraoperative lethality and no recurrence in 96.7 per cent of all cases, while Visick grades I on II were recorded from 98.2 per cent. Radiologically and gastroscopically detected pathological processes receded soon. Average postoperative reduction in acid secretion was 66.2 per cent in BAO and 46.8 per cent in MAO. Acid values re-increased thereafter, and three years later reduction rates still amounted to 43.7 per cent in BAO and 28.6 per cent in MAO. Indications for proximal gastric vagotomy are discussed in some detail.  相似文献   
106.
107.
The authors report a case of massive haemolytic anaemia with acute mitral valve regurgitation and left cardiac failure, which occurred one year after surgical reconstruction of the mitral valve for rupture of smaller leaflet chordae. Anaemia, mitral regurgitation and cardiac failure disappeared after mitral valve replacement, using a Carpentier Edwards No. 29 valve. Haemolytic anaemia following mitral valve reconstruction is exceptional. It seems to be due to the suture material lying in a turbulent regurgitation stream when mitral incompetence develops again.  相似文献   
108.
Wir berichten über den ersten Fall von polyzystischer lipomembran?ser Osteodysplasie oder “brain, bone and fat disease” in Deutschland. Die nach dem Erstbeschreibern auch als Morbus J?rvi-Hakola-Nasu bezeichnete Erkrankung ist bisher vor allem in Japan und in Finnland beschrieben worden. Einzelne F?lle wurden aus Schweden, Norwegen, Italien, Südafrika, Belgien und den USA berichtet. Im deutschsprachigen Raum ist bisher ein Fall aus ? ver?ffentlicht worden.  相似文献   
109.
To measure prefrontal and subcortical activity during a cognitive task, we examined 19 newly diagnosed schizophrenics and patients with schizophreniform psychosis. Seven healthy volunteers served as controls. The patients were drug naive or had received neuroleptics for a few days only. Cerebral blood flow distribution was depicted by single photon emission computed tomography at rest and during activation with the Wisconsin Card Sorting Test. A significant relative activation deficit in the left inferior-prefrontal region was revealed during the Wisconsin Card Sorting Test in the patient group. Furthermore, the patients had impaired striatal suppression on the left side during the cognitive task. The test performance was significantly impaired in the patients. The inability to reduce striatal activity may be due to a lack of corticostriatal feedback during prefrontal activation.  相似文献   
110.
Magnetic resonance imaging was employed to study the dependence of clot lysing patterns on two different modes of transport of urokinase into whole blood clots. In one group of clots (nonperfused clots, n1 = 10), access of urokinase to the fibrin network was possible by diffusion only, whereas in the other group (perfused clots, n2 = 10) bulk flow of plasma containing urokinase was instituted through occlusive clots by a pressure difference of 3.7 kPa (37 cm H2O) across 3 cm long clots with a diameter of 4 mm. It was determined separately that this pressure difference resulted in a volume flow rate of 5.05 +/- 2.4 x 10(-2) ml/min through occlusive clots. Perfused clots diminished in size significantly in comparison to nonperfused ones already after 20 min (p less than 0.005). Linear regression analysis of two-dimensional clot sizes measured by MRI showed that the rate of lysis was more than 50-times faster in the perfused group in comparison to the nonperfused group. It was concluded that penetration of the thrombolytic agent into clots by perfusion is much more effective than by diffusion. Our results might have some implications for understanding the differences in lysis of arterial and venous thrombi.  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