全文获取类型
收费全文 | 1246篇 |
免费 | 85篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 27篇 |
妇产科学 | 44篇 |
基础医学 | 146篇 |
口腔科学 | 38篇 |
临床医学 | 126篇 |
内科学 | 272篇 |
皮肤病学 | 4篇 |
神经病学 | 98篇 |
特种医学 | 110篇 |
外科学 | 142篇 |
综合类 | 43篇 |
预防医学 | 142篇 |
眼科学 | 3篇 |
药学 | 67篇 |
中国医学 | 2篇 |
肿瘤学 | 71篇 |
出版年
2021年 | 21篇 |
2019年 | 16篇 |
2018年 | 21篇 |
2016年 | 15篇 |
2015年 | 18篇 |
2014年 | 25篇 |
2013年 | 29篇 |
2012年 | 43篇 |
2011年 | 50篇 |
2010年 | 28篇 |
2009年 | 29篇 |
2008年 | 31篇 |
2007年 | 48篇 |
2006年 | 41篇 |
2005年 | 38篇 |
2004年 | 33篇 |
2003年 | 31篇 |
2002年 | 21篇 |
2001年 | 31篇 |
2000年 | 24篇 |
1999年 | 29篇 |
1998年 | 23篇 |
1997年 | 24篇 |
1995年 | 21篇 |
1994年 | 18篇 |
1993年 | 17篇 |
1992年 | 24篇 |
1991年 | 27篇 |
1990年 | 28篇 |
1989年 | 25篇 |
1988年 | 21篇 |
1987年 | 36篇 |
1986年 | 36篇 |
1985年 | 33篇 |
1984年 | 30篇 |
1983年 | 28篇 |
1982年 | 14篇 |
1980年 | 16篇 |
1979年 | 18篇 |
1978年 | 24篇 |
1977年 | 20篇 |
1976年 | 15篇 |
1975年 | 20篇 |
1973年 | 21篇 |
1972年 | 17篇 |
1971年 | 20篇 |
1970年 | 16篇 |
1969年 | 12篇 |
1967年 | 14篇 |
1966年 | 16篇 |
排序方式: 共有1360条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
R. B. Biggs R. M. Hanley P. R. Morrison F. W. Booth 《Mechanisms of ageing and development》1991,60(3):285-293
The concentration of mitochondria decrease in the heart as rodents age from maturity to senescence. The reason for this change is not known. One purpose of the present study was to determine if cytochrome c mRNA, representative of proteins of the inner mitochondrial membrane, decreased in the hearts of Fischer 344 rats as they aged from 12 to 24 months. Twenty-two percent less cytochrome c mRNA existed per given quantity of extracted RNA from the heart in 24-month-old rats as compared with the 12-month-old group. No change in the quantities of cardiac -actin mRNA, Ca2+/calmodulin protein kinase II mRNA or 18S rRNA was noted between 12- und 24-month-old hearts. Thus, the decrease in cytochrome c mRNA suggests that decreased in mRNAs for proteins of the inner mitochondrial membrane could play some role in the diminished concentration of mitochondria that exists in the senescent heart. 相似文献
5.
Airway responsiveness to histamine, substance P, methacholine and bilateral electrical vagal stimulation was assessed in capsaicin-treated and control guinea pigs. In animals treated with capsaicin (50 mg/kg s.c.) 7 days before experiments, airway responsiveness to histamine, substance P and vagal stimulation was significantly reduced but responsiveness to methacholine was unchanged. The findings suggest that histamine and substance P, but not methacholine, require capsaicin-sensitive sensory afferent nerves for part of their actions. 相似文献
6.
7.
8.
We report the findings of a two-year survey of faecal specimens for the protozoal pathogen, Cryptosporidium. Of the 2248 patients who were tested, 55 (2.5%) patients were found to have cryptosporidial infection. Transmission of the parasite appeared mainly to occur from person to person. In immunocompetent patients it caused an acute and sometimes severe gastroenteritis. Immunoincompetent patients experienced a variable illness that ranged from asymptomatic carriage to severe diarrhoea, causing malabsorption and ultimately death. Cryptosporidium is an important cause of gastroenteritis and may be the presenting feature of the acquired immunodeficiency syndrome. Therefore, it is pertinent to screen for this pathogen in all patients with acute diarrhoea. 相似文献
9.
Intestinal obstruction proximal to a transition zone without an interposed physical barrier usually indicates Hirschsprung disease. The authors report one case of focal small bowel muscular thinning just distal to a transition zone that produced clinical and radiographic findings that simulated long-segment Hirschsprung disease in a 2-day-old infant. 相似文献
10.
Image-directed percutaneous biopsies with a biopsy gun 总被引:3,自引:0,他引:3
Core tissue for histologic study is believed by many pathologists to be more diagnostic than material from needle aspiration. Recently, a biopsy "gun" has been introduced, which simplifies core biopsies. With this device, 182 biopsies of multiple anatomic sites were performed with ultrasonic, computed tomographic, and fluoroscopic guidance and 18-gauge needles. High-quality histopathologic specimens were obtained in 177 of the biopsies, and diagnostic target tissue was obtained in 167. Only three significant complications occurred: one bleeding complication that required transfusion and two cases of pneumothorax that necessitated placement of chest tubes. The biopsy gun eliminated the disjointed movements of conventional "skinny" needle biopsies, and none of the samples demonstrated significant "crush" artifact or obscuring blood, problems that are commonly associated with manual biopsy techniques. Patient discomfort was decreased with this system compared with that of manual biopsies, and the total procedure time was reduced. Because of these distinct advantages, the authors now use the biopsy gun exclusively for all percutaneous biopsies and recommend that other institutions consider the use of this biopsy method. 相似文献