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   105篇
  免费   7篇
儿科学   1篇
基础医学   8篇
临床医学   10篇
内科学   16篇
皮肤病学   7篇
特种医学   37篇
外科学   3篇
综合类   5篇
预防医学   16篇
药学   2篇
肿瘤学   7篇
  2021年   1篇
  2020年   1篇
  2017年   1篇
  2016年   1篇
  2015年   3篇
  2014年   2篇
  2013年   5篇
  2012年   5篇
  2011年   2篇
  2010年   3篇
  2009年   1篇
  2008年   2篇
  2007年   3篇
  2006年   4篇
  2005年   1篇
  2004年   3篇
  2003年   4篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1998年   3篇
  1997年   5篇
  1996年   2篇
  1995年   3篇
  1994年   3篇
  1993年   2篇
  1992年   5篇
  1991年   10篇
  1990年   2篇
  1989年   7篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1975年   1篇
  1974年   4篇
  1973年   1篇
  1969年   1篇
  1966年   2篇
排序方式: 共有112条查询结果,搜索用时 31 毫秒
1.
To assess the reproducibility and image quality of immediate postgadolinium chelate spoiled gradient-echo MRI in demonstrating disease of the abdominal aorta. All patients (27 patients: 21 men, 6 women) with substantial disease of the abdominal aorta, who underwent abdominal MR examinations at 1.5 T between 1991 and 1995, were entered in the study. Patients were referred for evaluation of suspected aortic disease (14 patients) or other abdominal diseases (13 patients). Three experienced investigators manually measured luminal and external aortic wall diameters and rated image quality, definition of inner and outer walls, extent of disease, and presence of other abdominal abnormalities, in an independent fashion. A cardiovascular surgeon then rated all studies to determine whether clinical management could be based on the MR findings alone. There was 98 to 99% agreement in measurements of luminal and external wall diameter between the three investigators. Overall image quality was rated as good in 77.8 to 88.9% of patients. A total of 31 additional nonaortic abdominal abnormalities were detected by all observers. The cardiovascular surgeon rated 25 of 27 studies as adequate to determine clinical management based on MR findings alone. Immediate postgadolinium spoiled gradient-echo MRI is a reproducible technique for the demonstration of abdominal aortic disease and possesses good image quality. Advantages of this technique include simultaneous evaluation of other nonvascular diseases of the abdomen, short examination time, and easy implementation as part of routine abdominal MRI scanning protocol.  相似文献   
2.
The computed tomographic (CT) findings of a right and left paraduodenal hernia are described. In the right paraduodenal hernia the major findings consist of encapsulation of small bowel loops in the right mid-abdomen with looping of arterial and venous jejunal branches behind the superior mesenteric artery. The findings of the left paraduodenal hernia are less specific and involve encapsulation of bowel loops at or above the level of the ligament of Treitz with intermittent dilatation.  相似文献   
3.
Small nodular lesions in the liver and spleen have been reported as an infrequent manifestation of sarcoidosis. Five patients with this appearance on either dynamic contrast material—enhanced computed tomographic (CT) or ultrasound scans underwent magnetic resonance (MR) imaging with and without dynamic gadolinium enhancement. The lesions were relatively uniform in size, ranging from 0.5 to 1.5 cm. On CT scans, they were hypoattenuating relative to surrounding parenchyma. On MR images, the lesions were hypointense relative to background parenchyma with all sequences. No substantial enhancement was observed in the lesions, although lesion conspicuity decreased over time on serial postcontrast images. Lesion conspicuity was greatest on either T2-weighted fat-suppressed (T2FS) images or early-phase dynamic contrast-enhanced images. Abdominal adenopathy was seen in three of the five patients and was hyperintense relative to liver on T2FS images in two and intermediate in intensity in one patient.  相似文献   
4.
Problems in suicide statistics for whites and blacks   总被引:2,自引:2,他引:0       下载免费PDF全文
The accuracy of suicide statistics was assessed by comparing published Health Department suicide rates for an area of New York City with Medical Examiner records. For the period 1968--1979, records from the Medical Examiner's Office were searched to determine all deaths classified as definite suicides. Another group of deaths was considered suicide by the Medical Examiner but never classified as such. These deaths we labeled "assigned suicides." When definite suicides were compared with all deaths considered suicide by the Medical Examiner (definite and assigned suicides), black suicide was underestimated by 80 per cent and white suicide by 42 per cent. Underestimation was the same for males and females but varied by age group. In 1968, when the seventh revision of the International Classification of Deaths (ICD) was used, Health Department suicide rates for blacks were almost identical to Medical Examiner rates, while white rates were underestimated by 25 per cent. In 1969--1970, when the eighth revision was used, Health Department statistics underestimated black suicides by 82 per cent and white suicides by 66 per cent. Reasons for the underestimations were related to the methods used in committing suicide by the two ethnic groups and to the ways that suicide classification has changed from the seventh to eighth revision. Implications for research using official death certificate reports are discussed.  相似文献   
5.
SVEP1 is a recently identified multidomain cell adhesion protein, homologous to the mouse polydom protein, which has been shown to mediate cell‐cell adhesion in an integrin‐dependent manner in osteogenic cells. In this study, we characterized SVEP1 function in the epidermis. SVEP1 was found by qRT‐PCR to be ubiquitously expressed in human tissues, including the skin. Confocal microscopy revealed that SVEP1 is normally mostly expressed in the cytoplasm of basal and suprabasal epidermal cells. Downregulation of SVEP1 expression in primary keratinocytes resulted in decreased expression of major epidermal differentiation markers. Similarly, SVEP1 downregulation was associated with disturbed differentiation and marked epidermal acanthosis in three‐dimensional skin equivalents. In contrast, the dispase assay failed to demonstrate significant differences in adhesion between keratinocytes expressing normal vs low levels of SVEP1. Homozygous Svep1 knockout mice were embryonic lethal. Thus, to assess the importance of SVEP1 for normal skin homoeostasis in vivo, we downregulated SVEP1 in zebrafish embryos with a Svep1‐specific splice morpholino. Scanning electron microscopy revealed a rugged epidermis with perturbed microridge formation in the centre of the keratinocytes of morphant larvae. Transmission electron microscopy analysis demonstrated abnormal epidermal cell‐cell adhesion with disadhesion between cells in Svep1‐deficient morphant larvae compared to controls. In summary, our results indicate that SVEP1 plays a critical role during epidermal differentiation.  相似文献   
6.
7.
8.
9.
10.
A 45-year-old patient with focal intrahepatic extramedullary hematopoiesis is presented in which the liver was imaged by CT, ultrasound, and MR. The appearance of the lesions on MR consisted of slightly increased signal on T2-weighted images with heterogeneous enhancement of some of the lesions during bolus infusion of gadolinium. The T1-weighted images postgadolinium showed no delayed enhancement.  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