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   704篇
  免费   41篇
  国内免费   10篇
儿科学   22篇
妇产科学   3篇
基础医学   54篇
口腔科学   10篇
临床医学   68篇
内科学   145篇
皮肤病学   30篇
神经病学   114篇
特种医学   47篇
外科学   95篇
综合类   40篇
预防医学   43篇
眼科学   13篇
药学   25篇
肿瘤学   46篇
  2023年   11篇
  2022年   14篇
  2021年   28篇
  2020年   11篇
  2019年   15篇
  2018年   9篇
  2016年   15篇
  2015年   18篇
  2014年   28篇
  2013年   34篇
  2012年   30篇
  2011年   25篇
  2010年   17篇
  2009年   13篇
  2008年   21篇
  2007年   19篇
  2006年   30篇
  2005年   15篇
  2004年   25篇
  2003年   8篇
  2002年   18篇
  2001年   15篇
  2000年   16篇
  1999年   17篇
  1998年   21篇
  1997年   9篇
  1996年   12篇
  1995年   11篇
  1994年   12篇
  1993年   7篇
  1992年   7篇
  1991年   11篇
  1990年   15篇
  1989年   20篇
  1988年   22篇
  1987年   14篇
  1986年   14篇
  1985年   11篇
  1984年   8篇
  1983年   7篇
  1982年   7篇
  1980年   6篇
  1979年   8篇
  1977年   7篇
  1976年   6篇
  1975年   6篇
  1974年   6篇
  1973年   7篇
  1972年   6篇
  1968年   6篇
排序方式: 共有755条查询结果,搜索用时 0 毫秒
1.
2.
The capacity of blood pressure cuffs to act as vehicles of hospital infection has been recognised. We describe the microbial flora of in-use DINAMAP blood pressure cuffs used in the operating theatres and one recovery room in a teaching hospital. Our results show significant microbial contamination of in-use blood pressure cuffs.  相似文献   
3.
Hyaluronan-dependent pericellular matrices or "coats" are expressed by a variety of cell types in culture and modulation of their expression may be important in regulation of cell interactions in vivo during development. Monoclonal antibody IVd4, which recognizes hyaluronan-binding protein with the properties of a hyaluronan receptor, was shown to block formation of these coats by a variety of cells. Using rat fibrosarcoma cells, it was found that the antibody not only blocked initial formation of the coats but also caused their loss when added subsequent to formation. The loss of preformed coats in the presence of antibody occurred at 4 degrees and 37 degrees, implying that the function of hyaluronan-binding protein in coat formation is not in mediating metabolic processes. The antibody also had no significant effect on hyaluronan production by the fibrosarcoma cells. In addition, hyaluronan hexasaccharide, a competitive inhibitor of the interaction between polymeric hyaluronan and its cell surface receptor, was found to inhibit coat formation. Thus it is concluded that a hyaluronan-binding protein with the properties of a hyaluronan receptor is required for pericellular matrix formation.  相似文献   
4.
An unusual giant cell tumor of the breast of a 72 year old man is reported. The microscopic and ultrastructural features of the tumor are presented in detail. Unusual and previously unreported myofibroblastic and myoepithelial differentiation of the spindle cell component is described. The possible histogenesis of the tumor is discussed.  相似文献   
5.
In order to assess the impact of variations in stroke care on outcomes, and to make geographic comparisons, the three Community Hospital-Based Stroke Programs in North Carolina, Oregon, and New York, aggregated their data on 4,132 hospitalized stroke patients. Complete demographic data or "Major Profile" were obtained on 2,390 (57.8%) of the 4,132 stroke patients. This includes those patients on whom informed patient and physician consents were obtained during the hospitalization. Of the major profile patients, 1,490 (62.3%) were followed for periods up to one year, 502 (21.0%) were lost to followup and 398 (16.6%) died within the one year followup period. Incomplete demographic data or "Minor Profile" were observed on 1,742 (42.1%) of the 4,132 patients. Minor profile includes those who died before comprehensive interviews were completed or those for whom informed consent for an interview could not be obtained. Of the minor profile group, 813 (46.7%) died in hospital, and 929 (53.3%) were alive when discharged from the hospital. This paper, which describes the programs, data collection procedures, and study cases, also highlights specific issues on stroke diagnosis, risk factors associated with stroke, and the influence of interventions on stroke outcomes. We conclude that: 1) the merging of data on hospitalized stroke cases from rural and urban hospitals in geographically distinct regions can be used in the study of stroke diagnosis, the use of diagnostic tests, and the effect of interventions on stroke outcomes; and 2) these data are consistent with the hypothesis that part of the national decline in mortality from stroke is due to a decline in stroke severity.  相似文献   
6.
BACKGROUND AND PURPOSE: MR imaging has revealed putative evidence of subclinical cerebrovascular disease (CVD) as reflected by white matter signal changes and infarct-like lesions (ILLs). Nonetheless, the prevalence of this condition in the general population has been defined only to a limited extent. We herein report the prevalence and anatomic characteristics of ILLs seen on cranial MR images obtained as part of a population-based study of cardiovascular disease in middle-aged adults. These results are contrasted to those of previous similar studies, particularly those of an elderly population in the Cardiovascular Health Study (CHS). METHODS: This Atherosclerosis Risk in Communities (ARIC) cohort consists of a probability sample of community-living persons who were 55 to 72 years old at the time of MR examination. MR imaging of 1890 participants was performed at two ARIC field centers, based on a common protocol. MR studies were evaluated by trained readers at the MR Reading Center using original digital data displayed on a high-resolution workstation. The measures of lesion size, anatomic location, and signal intensity were collected. The definition for an ILL was a non-mass, hyperintense region with an arterial vascular distribution on spin-density and T2-weighted images. RESULTS: Two hundred ninety participants had ILLs, for an overall prevalence of 15.3%. Eighty-two percent of participants with ILLs had lesions that were 3 mm or larger in maximal dimension, although 87% of these lesions were 20 mm or smaller in maximal dimension. The prevalence of ILLs increased with age, from 7.9% in the 55- to 59-year-old age group to 22.9% in the 65- to 72-year-old age group (P < .001). Lesion prevalence was greater in black (20.7%) than in white persons (10.2% [P < .0001]), but did not differ significantly between male and female participants. The basal ganglia and thalamic region was the most commonly affected anatomic site, accounting for 78.9% of the lesions. CONCLUSION: Considering that the prevalence of self-reported stroke or transient ischemic attack in ARIC participants is 1.5%, these results suggest that there is significantly more subclinical than clinical CVD in the general population. Furthermore, the prevalence of this subclinical disease increases with age, and is greater in black persons. ILLs are dominated by "lacunae" in the basal ganglia and thalamus. These results are, in general, similar to those of a comparable study of elderly participants in the CHS, except for a 60% lower prevalence of ILLs in this younger population.  相似文献   
7.
The records of the first 325 patients entered into the pilot phase of the National Traumatic Coma Data Bank were reviewed. Thirty-four severely head-injured patients who talked prior to deteriorating to a Glasgow Coma Scale (GCS) score of 8 or less were identified. Of those 34 patients, 18 died or were left vegetative and 16 recovered. While there were certain common factors between those who talked and died and those who talked and recovered, there were also significant differences. The common factors between the two groups were the length of time to deterioration or operative intervention (16 versus 18 hours, respectively), and the initial GCS scores (12.6 versus 12.4, respectively). The primary differences between the groups included the mean age, the degree of midline shift seen on computerized tomography (CT), and the presence of subdural hematoma. Those who talked at some point postinjury, but who subsequently died, had a mean age of 50 years. Those who talked, deteriorated, and then recovered were found to have a mean age of 32 years. Seven of the 18 patients who talked and died had a shift of greater than 15 mm on CT, while this degree of shift was demonstrated in only one of 16 patients who talked, deteriorated, and recovered. Subdural hematomas were significantly more common in the "talk and die" group, as was the overall need for operation. Since the overwhelming majority of patients with marked shift on CT have surgical lesions, early operative intervention is strongly recommended in these patients, prior to their inevitable deterioration.  相似文献   
8.
9.
10.
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