首页 | 官方网站   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   544篇
  免费   65篇
  国内免费   5篇
医药卫生   614篇
  2022年   5篇
  2021年   3篇
  2020年   4篇
  2019年   6篇
  2018年   9篇
  2017年   7篇
  2016年   10篇
  2015年   16篇
  2014年   20篇
  2013年   21篇
  2012年   18篇
  2011年   15篇
  2010年   44篇
  2009年   31篇
  2008年   19篇
  2007年   14篇
  2006年   19篇
  2005年   21篇
  2004年   9篇
  2003年   13篇
  2002年   8篇
  2001年   7篇
  2000年   6篇
  1999年   15篇
  1998年   28篇
  1997年   35篇
  1996年   35篇
  1995年   29篇
  1994年   18篇
  1993年   17篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1989年   12篇
  1988年   15篇
  1987年   16篇
  1986年   11篇
  1985年   9篇
  1984年   4篇
  1983年   4篇
  1982年   6篇
  1981年   10篇
  1980年   4篇
  1979年   2篇
  1978年   1篇
  1977年   5篇
  1976年   5篇
  1973年   1篇
  1971年   1篇
  1954年   1篇
排序方式: 共有614条查询结果,搜索用时 31 毫秒
71.
Hamlin  JA; Friedman  M; Stein  MG; Bray  JF 《Radiology》1986,158(1):199-202
We have reviewed our experience with 118 biliary catheterization procedures in 109 patients from 1979 to 1984. Major complications (septic shock, hemorrhage, subphrenic abscess, and formation of an arteriovenous fistula) occurred in five patients (4.2%), three of whom died (2.5%). Minor complications occurred in 41 patients. Our success rate using the procedure was 97%. The complications that occurred are described.  相似文献   
72.
Objective: This study was designed to compare the results of preliminary evaluation, ovarian hyperstimulation, and monitoring of patients at a distant in vitro fertilization satellite center with those treated at the main campus of the program.Study design: Fifty-four patients completing oocyte retrieval cycles at the Eugene satellite Oregon Health Sciences University in vitro fertilization program for the period Jan. 1, 1991, through Dec. 31, 1993, were compared with 222 patients at the main campus for age, peak estradiol level, number of oocytes, retrieved, number of embryos, clinical pregnancy rate, and pregnancy outcome.Results: There were no statistically significant differences between the Eugene in vitro fertilization satellite center and the main campus for any of the factors analyzed with the exception of clinical pregnancy rate. The clinical pregnancy rate per cycle at the Eugene satellite center was 39% while the Portland main campus rate was 23% (p = 0.027), presumably because of a larger number of couples with severe male factor infertility at the central site.Conclusion: A distant in vitro fertilization satellite program was highly successful in the Oregon experience. In addition to greater convenience to the patients, the program was highly comparable to main campus program in measured parameters of ovarian hyperstimulation, oocyte retrieval, number of embryos, and pregnancy rate.  相似文献   
73.
MG  Bruzzone  M  Grisoli  T  De  Simone  C  Regna-Gladin  毛成洁 《中华脑血管病论坛》2005,3(2):188-190
眩晕患者的诊断过程始于对病史以及随后的全身体格检查和神经系统检查的准确评价。这步骤通常能够识别确切的病因,或者至少可鉴别周围性眩晕和中枢性眩晕。神经放射学检查必须作为选择性诊断手段加以考虑,包括CT、MRI、MR血管造影(MRA)以及血管造影术。对于周围性眩晕、良性阵发性位置性眩晕、迷路炎、Meniere病、外淋巴瘘、局部外伤、中毒性迷路炎、急性中耳炎和慢性中耳渗液等疾病的诊断而言,影像学技术的作用是有争议的。CT和MR可用来排除其他病理学原因和证实诊断。分辨率和增加和能够增强迷路内液的特殊MRI序列的应用,使我们能够对迷路的结构和病理学变化进行更详细地分析。T1和T2对比序列检查都是必需的。当怀疑中耳类以及在外伤后眩晕随访时,需要进行高分辨率CT检查。中枢性眩晕的病因很多,包括椎基底循环血管病变、多发性硬化、偏头痛相关性眩晕、小脑和脑干肿瘤以及中枢神经系统感染,其中脑缺血和多发性硬化最为常见。在这些情况下,影像学检查应该是强制性的。CT能够诊断大多数小脑出血以及小脑和脑干的急性缺血,增强的MRI已经证实是检测后颅窝病病变最为敏感的工具。弥散加权MRI能够比常规MRI更早地显示急性缺血性改变。MRA能提供类似血管造影片的颅内血管图像。有证据表明,有时可避免进行侵入性的血管造影术。MRA的分辨率不如传统的血管造影术,还可能受到活动和其他伪影的影响。选择性的后循环血管造影通常对治疗决策有提示作用。  相似文献   
74.
We compared the morphological characteristics of layer III pyramidal neurones in different visual areas of the occipitotemporal cortical 'stream', which processes information related to object recognition in the visual field (including shape, colour and texture). Pyramidal cells were intracellularly injected with Lucifer Yellow in cortical slices cut tangential to the cortical layers, allowing quantitative comparisons of dendritic field morphology, spine density and cell body size between the blobs and interblobs of the primary visual area (V1), the interstripe compartments of the second visual area (V2), the fourth visual area (V4) and cytoarchitectonic area TEO. We found that the tangential dimension of basal dendritic fields of layer III pyramidal neurones increases from caudal to rostral visual areas in the occipitotemporal pathway, such that TEO cells have, on average, dendritic fields spanning an area 5-6 times larger than V1 cells. In addition, the data indicate that V1 cells located within blobs have significantly larger dendritic fields than those of interblob cells. Sholl analysis of dendritic fields demonstrated that pyramidal cells in V4 and TEO are more complex (i.e. exhibit a larger number of branches at comparable distances from the cell body) than cells in V1 or V2. Moreover, this analysis demonstrated that the dendrites of many cells in V1 cluster along specific axes, while this tendency is less marked in extrastriate areas. Most notably, there is a relatively large proportion of neurones with 'morphologically orientation-biased' dendritic fields (i.e. branches tend to cluster along two diametrically opposed directions from the cell body) in the interblobs in V1, as compared with the blobs in V1 and extrastriate areas. Finally, counts of dendritic spines along the length of basal dendrites revealed similar peak spine densities in the blobs and the interblobs of V1 and in the V2 interstripes, but markedly higher spine densities in V4 and TEO. Estimates of the number of dendritic spines on the basal dendritic fields of layer III pyramidal cells indicate that cells in V2 have on average twice as many spines as V1 cells, that V4 cells have 3.8 times as many spines as V1 cells, and that TEO cells have 7.5 times as many spines as V1 cells. These findings suggest the possibility that the complex response properties of neurones in rostral stations in the occipitotemporal pathway may, in part, be attributed to their larger and more complex basal dendritic fields, and to the increase in both number and density of spines on their basal dendrites.   相似文献   
75.
76.
77.
78.
79.
80.
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-23

京公网安备 11010802026262号